Automatic transmission

ABSTRACT

A reduced rotation output unit for outputting a reduced rotation obtained by reducing rotation of an input shaft is arranged at one side of a planetary gear unit in an axial direction, a first clutch and a second clutch are interposed between a second rotation element of the planetary gear unit, and a third rotation element and the input shaft are arranged at the other side of the planetary gear unit in the axial direction, and an output member is arranged between the first clutch, the second clutch and the planetary gear unit. Accordingly, it is possible to position the reduced rotation output unit and the planetary gear unit close to each other, and it is possible to make a transmission member, that transmits the reduced rotation output from the reduced rotation output unit to the planetary gear unit, short.

[0001] This application claims priority from JP 2002-382147, filed Dec.27, 2002; JP 2002-204894, filed Jul. 12, 2002; and JP 2002-098020, filedMar. 29, 2002 through PCT/JP 03/04112, filed Mar. 31, 2003, thedisclosures of which are incorporated herein by reference thereto.

TECHNICAL FIELD

[0002] The invention relates to an automatic transmission mounted in avehicle or the like, and more particularly to an arrangement of anautomatic transmission in which a multi-speed shift that can result fromselectively inputting a reduced rotation to one rotation element in aplanetary gear unit.

BACKGROUND OF THE INVENTION

[0003] In general, in an automatic transmission mounted in a vehicle orthe like, the structure is provided with a planetary gear unit in whichtwo lines of planetary gears are connected, and a planetary gear whichcan selectively output a reduced rotation obtained by reducing arotation of an input shaft (for example, refer to Japanese PatentLaid-Open Publications Nos. 4-125345 and 2000-274498). The art describedin these documents achieves, for example, six forward speeds and onebackward speed by selectively inputting the reduced rotation from theplanetary gear via a clutch to one rotation element in the planetarygear unit having, for example, four rotation elements.

[0004] Note that, the automatic transmission described above is providedwith a plurality of clutches for inputting the rotation of the inputshaft to the rotation elements in the planetary gear unit and therotation elements in the planetary gear. However, depending on thearrangement of the plurality of clutches, there is a case when a memberthat transmits the reduced rotation of the planetary gear to therotation elements in the planetary gear unit must be made longer in anaxial direction. Further, in particular, in an automatic transmissionused in a FF (front engine and front drive) vehicle, or the like, anautomatic transmission is used that has a gear for outputting an outputrotation of the automatic transmission to another parallel shaft, aso-called counter gear, that is provided for a driven wheel. In the casethat the counter gear is arranged at the same manner between theplanetary gear unit and the planetary gear, the member that transmitsthe reduced rotation has to be made longer in an axial directiondepending on the arrangement of the counter gear.

SUMMARY OF THE INVENTION

[0005] Making the member that transmits the reduced rotation longerrequires, in other words, making the member that transmits a largertorque longer. Providing a long member capable of enduring the largetorque requires that the member be a comparatively thick member, wherebyprovision of a compact configuration of the automatic transmission isinhibited. Further, the member described above becomes heavier, therebyinhibiting weight saving in the automatic transmission. Further, inertia(inertia force) is increased, and there is a tendency for shift shock tobe generated due to a reduction in controllability of the automatictransmission.

[0006] Accordingly, an object of the invention is to provide anautomatic transmission in which a reduced rotation output unit isarranged at one side of a planetary gear unit in an axial direction,first and second clutches are arranged at the other side of theplanetary gear unit in the axial direction, and an output member isarranged between the first and second clutches and the planetary gearunit. Accordingly, the problem described above is solved.

[0007] The automatic transmission according to the invention is usefulfor an automatic transmission mounted in vehicles, such as passengercars, trucks, buses, or the like, and is more particularly suitable foruse in vehicles requiring compactness and reduced weight for ease ofvehicle mounting, and in addition, in vehicles requiring reduced shiftshock.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The invention will be described with reference to the drawings,in which:

[0009]FIG. 1 is a cross sectional development view showing an automatictransmission in accordance with a first embodiment;

[0010]FIG. 2 is a cross sectional view showing an automatic speed changemechanism of the automatic transmission in accordance with the firstembodiment;

[0011]FIG. 3 is a schematic view showing the automatic transmission inaccordance with the first embodiment;

[0012]FIG. 4 is an engagement table for the automatic transmission inaccordance with the first embodiment;

[0013]FIG. 5 is a velocity diagram of the automatic transmission inaccordance with the first embodiment;

[0014]FIG. 6 is a cross sectional development view showing an automatictransmission in accordance with a second embodiment;

[0015]FIG. 7 is a cross sectional view showing an automatic speed changemechanism of the automatic transmission in accordance with the secondembodiment;

[0016]FIG. 8 is a schematic view showing the automatic transmission inaccordance with the second embodiment;

[0017]FIG. 9 is an engagement table for the automatic transmission inaccordance with the second embodiment;

[0018]FIG. 10 is a velocity diagram of the automatic transmission inaccordance with the second embodiment;

[0019]FIG. 11 is a cross sectional view showing an automatic speedchange mechanism of an automatic transmission in accordance with a thirdembodiment;

[0020]FIG. 12 is a schematic view showing the automatic transmission inaccordance with the third embodiment;

[0021]FIG. 13 is an engagement table for the automatic transmission inaccordance with the third embodiment;

[0022]FIG. 14 is a velocity diagram of the automatic transmission inaccordance with the third embodiment;

[0023]FIG. 15 is a cross sectional view showing an automatic speedchange mechanism of an automatic transmission in accordance with afourth embodiment;

[0024]FIG. 16 is a schematic view showing the automatic transmission inaccordance with the fourth embodiment;

[0025]FIG. 17 is an engagement table for the automatic transmission inaccordance with the fourth embodiment;

[0026]FIG. 18 is a velocity diagram of the automatic transmission inaccordance with the fourth embodiment;

[0027]FIG. 19 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance with afifth embodiment;

[0028]FIG. 20 is an engagement table for the automatic transmission inaccordance with the fifth embodiment;

[0029]FIG. 21 is a velocity diagram of the automatic transmission inaccordance with the fifth embodiment;

[0030]FIG. 22 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance with asixth embodiment;

[0031]FIG. 23 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance with aseventh embodiment;

[0032]FIG. 24 is an engagement table for the automatic transmission inaccordance with the seventh embodiment;

[0033]FIG. 25 is a velocity diagram of the automatic transmission inaccordance with the seventh embodiment;

[0034]FIG. 26 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance withan eighth embodiment;

[0035]FIG. 27 is an engagement table for the automatic transmission inaccordance with the eighth embodiment;

[0036]FIG. 28 is a velocity diagram of the automatic transmission inaccordance with the eighth embodiment;

[0037]FIG. 29 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance with aninth embodiment;

[0038]FIG. 30 is an engagement table for the automatic transmission inaccordance with the ninth embodiment;

[0039]FIG. 31 is a velocity diagram of the automatic transmission inaccordance with the ninth embodiment;

[0040]FIG. 32 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance with atenth embodiment;

[0041]FIG. 33 is an engagement table for the automatic transmission inaccordance with the tenth embodiment;

[0042]FIG. 34 is a velocity diagram of the automatic transmission inaccordance with the tenth embodiment;

[0043]FIG. 35 is a schematic cross sectional view showing an automaticspeed change mechanism of an automatic transmission in accordance withan eleventh embodiment;

[0044]FIG. 36 is an engagement table for the automatic transmission inaccordance with the eleventh embodiment; and

[0045]FIG. 37 is a velocity diagram of the automatic transmission inaccordance with the eleventh embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0046] The invention will be described in detail. However, broadlydescribed, an automatic transmission includes an input shaft thatrotates on the basis of an output rotation of a drive power source; aplanetary gear unit having first, second, third and fourth rotationelements; a reduced rotation output unit for selectively outputting areduced rotation obtained by reducing rotation of the input shaft to thefirst rotation element; a first clutch interposed between the inputshaft and the second rotation element; a second clutch interposedbetween the input shaft and the third rotation element; and an outputmember that outputs rotation of the fourth rotation element to a drivenwheel transmission mechanism, in which the reduced rotation output unitis arranged at one side of the planetary gear unit in an axialdirection, the first and second clutches are arranged at the other sideof the planetary gear unit in the axial direction, and the output memberis arranged between the first and second clutches and the planetary gearunit.

[0047] As a result, it is possible to position the reduced rotationoutput unit and the planetary gear close to each other without having toprovide, for example, a clutch and an output member therebetween, and itis possible to make a member (for example, a transmission member, asleeve member, or the like) that transmits the reduced rotationcomparatively short. Therefore, it is possible to achieve a compactstructure and weight saving of the automatic transmission, and it ispossible to reduce the inertia (the inertia force). Accordingly, it ispossible to improve the controllability of the automatic transmissionand it is possible to reduce the generation of shift shock.

[0048] Also, in the invention, an automatic transmission is configuredsuch that the first clutch is connected to the second rotation elementvia an inner peripheral side of the output member, and the second clutchis connected to the third rotation element via an outer peripheral sideof the first clutch and an inner peripheral side of the output member.

[0049] As a result, it is possible to prevent the member that connectseach of the rotation elements from being complicated, and it is possibleto make the automatic transmission compact.

[0050] In a variant of the invention, the configuration is such that thefirst clutch has a friction disk that is spline engaged at an innerperipheral side to a member that connects to the second rotationelement; a first clutch drum which internally houses a hydraulic servo,which is spline engaged to an outer peripheral side of the frictiondisk, and which is connected to the input shaft; a first piston thatpresses the friction disk; and a first hydraulic servo oil pressurechamber which is formed between an inner peripheral side of the firstpiston and the input shaft and between an outer peripheral side and thefirst clutch drum by sealing in a fluid tight manner, and the secondclutch has a friction disk that is spline engaged at an inner peripheralside to the first clutch drum; a second clutch drum which internallyhouses a hydraulic servo, which is spline engaged to an outer peripheralside of the friction disk, and which is connected to the third rotationelement; a second piston that presses the friction disk; and a secondhydraulic servo oil pressure chamber formed between an inner peripheralside and an outer peripheral side of the second piston and the secondclutch drum by sealing in a fluid tight manner.

[0051] As a result, the first clutch is structured such that the secondclutch is positioned at an outer peripheral side thereof, and thus cannot have its diameter enlarged to the outer peripheral side. However, itis possible to ensure that the hydraulic servo, and more particularly, apressure receiving area of the first hydraulic servo oil chamber, islarge at the inner peripheral side by arranging the hydraulic servo onthe input shaft (in comparison to when, for example, the hydraulic servois provided on the boss portion), and it is possible to increase acapacity of the first clutch.

[0052] Further, in another variant of the invention, the configurationis such that the first clutch has a friction disk which is splineengaged at an inner peripheral side to a member that connects to thesecond rotation element; a first clutch drum which internally houses ahydraulic servo, which is spline engaged to an outer peripheral side ofthe friction disk, and which is connected to the input shaft; a firstpiston that presses the friction disk; and a first hydraulic servo oilpressure chamber formed between an inner peripheral side of the firstpiston and the input shaft, and between an outer peripheral side and thefirst clutch drum by sealing in a fluid tight manner, and the secondclutch has a friction disk which is spline engaged at an innerperipheral side to the third rotation element; a second clutch drumwhich internally houses a hydraulic servo, which is spline engaged to anouter peripheral side of the friction disk, and which is arranged at anouter peripheral side of the first clutch drum and connected to theinput shaft; a second piston that presses the friction disk; and asecond hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the second piston andthe second clutch drum by sealing in a fluid tight manner.

[0053] As a result, the first clutch is structured such that the secondclutch is positioned at an outer peripheral side thereof, and thuscannot have its diameter enlarged at the outer peripheral side. However,it is possible to ensure that the hydraulic servo, and moreparticularly, a pressure receiving area of the first hydraulic servo oilchamber, is large at the inner peripheral side by arranging thehydraulic servo on the input shaft (in comparison to when, for example,the hydraulic servo is provided on the boss portion), and it is possibleto increase a capacity of the first clutch.

[0054] In the invention, the reduced rotation output unit is configuredso as to have a speed reduction planetary gear, and the speed reductionplanetary gear, the planetary gear unit and the output member areprovided coaxially with the input shaft.

[0055] As a result, in particular, in the case that the automatictransmission is mounted in an FF vehicle, it is possible to make thedriven wheel transmission mechanism (for example, a counter shaftportion or the like) compact (in comparison with the case, for example,that the speed reduction planetary gear and the like are provided onanother shaft). Thus, for example, it is possible to preventinterference, for example, with a vehicle body member, and it ispossible to improve the ease of mounting the automatic transmission.

[0056] In a form of the invention, the reduced rotation output unit isconfigured to include the speed reduction planetary gear which has aninput rotation element that inputs rotation of the input shaft, a fixedelement that fixes rotation, an output rotation element that is alwaysconnected to the first rotation element, and a first brake capable offixing rotation of the fixed element, in which reduced rotation can beoutput by engaging the first brake.

[0057] As a result, the first brake is capable of fixing the rotation ofthe fixed element connects and disconnects the output of the reducedrotation. Accordingly, it is possible to make the first brake compact,for example, in comparison with a clutch connecting and disconnectingthe reduced rotation, and it is possible to position the reducedrotation output unit close to the planetary gear unit. Thus, it ispossible to achieve a compact structure and weight saving of theautomatic transmission.

[0058] In another form of the invention, the reduced rotation outputunit is configured so as to include the speed reduction planetary gearwhich has an input rotation element that inputs rotation of the inputshaft, a fixed element that fixes rotation, and an output rotationelement that is always connected to the first rotation element, a thirdclutch interposed between the input shaft and the input rotationelement, and a first brake capable of fixing rotation of the fixedelement, in which reduced rotation can be output by engaging the thirdclutch and the first brake.

[0059] As a result, the third clutch interposed between the input shaftand the input rotation element and the first brake is capable of fixingthe rotation of the fixed element connect and disconnect the output ofthe reduced rotation. Accordingly, it is possible to make the thirdclutch and the first brake compact, for example, in comparison with aclutch connecting and disconnecting the reduced rotation, and it ispossible to arrange the reduced rotation output unit close to theplanetary gear unit. Thus, it is possible to achieve a compact structureand weight saving of the automatic transmission.

[0060] In yet another form of the invention, the reduced rotation outputunit is configured so as to include the speed reduction planetary gearwhich has an input rotation element that always inputs rotation of theinput shaft, a fixed element that always fixes rotation, and an outputrotation element that always connects to the first rotation element, anda third clutch interposed between the input shaft and the input rotationelement, in which reduced rotation can be output by engaging the thirdclutch.

[0061] As a result, the third clutch, interposed between the input shaftand the input rotation element, connects and disconnects of the outputof the reduced rotation. Accordingly, it is possible to make the thirdclutch compact, for example, in comparison with a clutch connecting anddisconnecting the reduced rotation, and it is possible to arrange thereduced rotation output unit close to the planetary gear unit.Therefore, it is possible to achieve a compact structure and weightsaving of the automatic transmission.

[0062] In another form of the invention, the reduced rotation outputunit is configured so as to include the speed reduction planetary gearwhich has an input rotation element that always inputs rotation of theinput shaft, a fixed element that always fixes rotation, an outputrotation element that connects to the first rotation element, and athird clutch interposed between the first rotation element and theoutput rotation element, in which reduced rotation can be output byengaging the third clutch.

[0063] As a result, the third clutch, interposed between the firstrotation element and the output rotation element, connects anddisconnects the output of the reduced rotation. Accordingly, forexample, by disengaging the third clutch, it is possible to make therotation of the input shaft input to the input rotation element rotateidly using the planetary gear, while it is also possible to selectivelyoutput reduced rotation to the first rotation element. Thus, it ispossible to directly fix, for example, the element fixing the rotationto the case, or the like, without providing a brake, and it is possibleto achieve a compact structure and weight saving of the automatictransmission.

[0064] In many forms of the invention, the first clutch, the secondclutch and the third clutch have respective hydraulic servos, thehydraulic servo of the second clutch arranged on a first boss portionthat extends from one end of the case and communicates with an oilpassage provided in the first boss portion, the hydraulic servo of thefirst clutch being arranged on one end of the input shaft andcommunicates with an oil passage in one end of the first boss portion orthe case via an oil passage provided within the input shaft, and thehydraulic servo of the third clutch arranged on a second boss portionthat extends from the other end of the case or the other end of theinput shaft and communicates with an oil passage provided in the secondboss portion or an oil passage provided within the input shaft.

[0065] As a result, the hydraulic servo of the first clutch is providedon one end of the input shaft. Accordingly, it is possible to supply theoil to the hydraulic servo by supplying the oil to the oil passageprovided within the input shaft while preventing leakage from the caseby using a pair of sealing rings, for example, without providing asealing ring between the input shaft and the hydraulic servo. Further,the hydraulic servos of the second and third clutches can supply the oilfrom the boss portion that extends from the case, for example, withoutpassing it through other members, that is, the oil can be supplied byrespectively providing a pair of sealing rings. Accordingly, the oil canbe supplied to the three hydraulic servos by simply arranging therespective pairs of sealing rings. Thus, it is possible to minimizesliding resistance that results from the sealing ring, and it ispossible to improve the efficiency of the automatic transmission.

[0066] In some forms of the invention, the first clutch, the secondclutch and the third clutch have respective hydraulic servos, thehydraulic servo of the second clutch being arranged on a first bossportion that extends from one end of the case and communicates with anoil passage provided in the first boss portion, the hydraulic servo ofthe first clutch being arranged on one end of the input shaft andcommunicates with an oil passage in one end of the first boss portion orthe case via an oil passage provided within the input shaft, and thehydraulic servo of the third clutch being arranged on one end of theinput shaft and communicates with an oil passage arranged on the otherend of the input shaft and provided within the input shaft.

[0067] As a result, the hydraulic servo of the first clutch is providedon one end of the input shaft. Accordingly, it is possible to supply theoil to the hydraulic servo by supplying the oil to the oil passageprovided within the input shaft while preventing leakage from the caseby using a pair of sealing rings, for example, without providing asealing ring between the input shaft and the hydraulic servo. Thehydraulic servo of the second clutch can supply the oil from the bossportion that extends from the case, for example, without passing itthrough other members. Further, because the hydraulic servo of the thirdclutch is arranged on the input shaft, and the oil is supplied to theoil passage provided within the input shaft while preventing leakagefrom the case by using a pair of sealing rings, the oil can be suppliedto the hydraulic servo, for example, without providing a sealing ringbetween the input shaft and the hydraulic servo. In other words, the oilcan be supplied by arranging a pair of sealing rings, respectively.Accordingly, the oil can be supplied to three hydraulic servos by simplyproviding a respective pair of sealing rings. Thus, it is possible tominimize sliding resistance that results from the sealing ring, and itis possible to improve the efficiency of the automatic transmission.Further, because the hydraulic servos of the first and third clutchesare arranged on the input shaft, and are respectively arranged so as tobe separated to one end side and the other end side of the input shaft,it is not necessary to provide the oil passages for the hydraulic servossuch that they overlap within the input shaft. Thus, it is possible tomake the input shaft narrow and it is possible to make the automatictransmission compact.

[0068] In many forms of the invention, the third clutch is configured tohave a friction disk that is spline engaged at an inner peripheral sideto a member connected to the input rotation element or the outputrotation element of the planetary gear, a third clutch drum whichinternally houses a hydraulic servo and which is spline engaged to anouter peripheral side of the friction disk, a third piston that pressesthe friction disk, and a first hydraulic servo oil pressure chamberformed between an inner peripheral side and an outer peripheral side ofthe third piston and the third clutch drum by sealing in a fluid tightmanner. The friction disk is arranged at a position where at least apart thereof overlaps with an outer peripheral side of the speedreduction planetary gear in a diametrical direction, the third clutchdrum is arranged so as to open in the direction of the speed reductionplanetary gear, and the speed reduction planetary gear is positionedbetween the hydraulic servo of the third clutch and the planetary gearunit in an axial direction.

[0069] As a result, the friction disk is arranged at the outerperipheral side of the speed reduction planetary gear in the axialdirection, and it is possible to make the automatic transmission compactin the axial direction. Further, the speed reduction planetary gear isarranged between the hydraulic servo of the third clutch and theplanetary gear unit in the axial direction. Accordingly, the speedreduction planetary gear and the planetary gear unit can be positionedadjacent to each other (as the hydraulic servo of the third clutch isnot provided between the speed reduction planetary gear and theplanetary gear unit), and it is possible to make the member (forexample, the transmission member, the sleeve member or the like), thattransmits the reduced rotation, comparatively short. Accordingly, it ispossible to achieve a compact structure and weight saving of theautomatic transmission, and it is possible to reduce the inertia (theinertia force). Therefore, it is possible to improve the controllabilityof the automatic transmission, and it is possible to reduce thegeneration of shift shock.

[0070] In the invention, the speed reduction planetary gear can beconfigured from a double pinion planetary gear. As a result, it ispossible to output the rotation of the input shaft as the reducedrotation and, in addition, the respective rotation elements, such as theplanetary gear unit and the speed reduction planetary gear, do not needto be large even in the case that a gear ratio of the automatictransmission is set favorably. Thus high speed rotation can beinhibited. Accordingly, it is possible to make the automatictransmission compact.

[0071] In the invention, the speed reduction planetary gear can have afirst carrier that corresponds to the input rotation element, a firstsun gear that corresponds to the fixed element, and a first ring gearcorresponding to the output rotation element. As a result, it ispossible to output the rotation of the input shaft as the reducedrotation.

[0072] Alternatively, the speed reduction planetary gear can have afirst sun gear that corresponds to the input rotation element, a firstcarrier that corresponds to the fixed element, and a first ring gearthat corresponds to the output rotation element. As a result, it ispossible to output the rotation of the input shaft as the reducedrotation.

[0073] Further, in the invention, the planetary gear unit can be aRavigneaux type planetary gear configured from a second sun gear, athird sun gear, a second carrier and a second ring gear. The firstrotation element is configured from the second sun gear which inputs theoutput rotation of the reduced rotation output unit and which isselectively fixable on the basis of engagement of the second brake, thesecond rotation element is configured from the third sun gear whichinputs the rotation of the input shaft on the basis of engagement of thefirst clutch, the third rotation element is configured from the secondcarrier which has a long pinion that meshes with the second sun gear anda short pinion that meshes with the third sun gear, which is selectivelyfixable on the basis of engagement of the third brake, and which inputsthe rotation of the input shaft on the basis of engagement of the secondclutch, and the fourth rotation element is configured from the secondring gear which meshes with the long pinion.

[0074] As a result, it is possible to position the reduced rotationoutput unit and the planetary gear unit close to each other while it ispossible to achieve, for example, six forward speeds and one backwardspeed. Further, it is possible to make the member that transmits thereduced rotation comparatively short.

[0075] When the planetary gear unit is as above, in the invention, theconfiguration includes a first one-way clutch for restricting therotation of the carrier to one direction which is provided in parallelto the third brake. As a result, it is possible to achieve, for example,a forward first speed state at a time of normal running on the basis ofengagement of the first clutch and the first one-way clutch.Accordingly, it is possible to smoothly achieve the forward first speed,for example, at a time of changing from a non-running range to a runningrange.

[0076] In such a planetary gear unit of the invention, the configurationis such that the third brake is arranged at an outer peripheral side ofthe planetary gear unit, and the first one-way clutch is arrangedadjacent to the second clutch.

[0077] As a result, the configuration realizes the backward first speedby engaging the third brake along with engagement of the third clutchthat connects and disconnects the reduced rotation while the firstone-way clutch is engaged along with the first clutch that inputs therotation of the input shaft when the forward first speed is realized.Accordingly, a reaction force torque applied to the third brake becomesgreater than a reaction force torque applied to the first one-wayclutch. Therefore, it is possible to make the member that transmits thetorque resulting from the reduced rotation to the third brakecomparatively short, by positioning the third brake close to the outerperipheral side of the planetary gear unit. Further, in the case thatthe first one-way clutch is positioned close to the second clutch andapart from the planetary gear unit, it is not necessary to make themember that connects the second clutch and the second carrier large.Further, because the first one-way clutch is not positioned at the outerperiphery of the planetary gear unit, it is possible to improve thedesign freedom of the brake. Accordingly, it is possible to achieve acompact structure and weight saving of the automatic transmission.

[0078] Alternatively, in such a planetary gear unit of the invention,the configuration is such that the third brake and the first one-wayclutch are arranged at an outer peripheral side of the planetary gearunit.

[0079] As a result, it is possible to position the output member closeto, for example, the torque converter (because the portion where thefirst and second clutches are arranged can be made compact in the axialdirection in comparison with the case, for example, that the firstone-way clutch is provided adjacent to the first clutch). Accordingly,it is possible to make the driven wheel transmission mechanism portion(in particular, the counter shaft portion) compact in the axialdirection.

[0080] In such a planetary gear unit of the invention, the configurationincludes a second one-way clutch which is arranged in parallel to thesecond brake and which restricts the rotation of the second sun gear toone direction on the basis of the engagement of a fourth brake. As aresult, it is possible to smoothly execute shifting, for example, fromthe forward second speed to the forward third speed.

[0081] Such a configuration includes a sleeve member which is interposedbetween the reduced rotation output unit and the second sun gear andwhich connects the output rotation of the reduced rotation output unitto the rotation of the second sun gear, and an inner race of the secondone-way clutch and the sleeve member are integrally formed. As a result,it is possible to make the automatic transmission compact while shiftingfrom the forward second speed to the forward third speed can be smoothlyexecuted.

[0082] As a result, it is possible to position the reduced rotationoutput unit and the planetary gear unit close to each other while thesix forward speeds and the one backward speed can be achieved.Accordingly, it is possible to make the member that transmits thereduced rotation comparatively short. Therefore, it is possible toachieve a compact structure and weight saving in the automatictransmission, and it is possible to make the inertia (the inertia force)small. Thus, it is possible to improve the controllability of theautomatic transmission, and to reduce the generation of shift shock.

[0083] Further, the configuration is such that a forward first speed isachieved on the basis of engagement of the first clutch and the thirdbrake, a forward second speed is achieved on the basis of engagement ofthe first clutch and the second brake, a forward third speed resultsfrom engaging the first clutch and setting a state in which reducedrotation is output from the reduced rotation output unit, a forwardfourth speed is achieved on the basis of engagement of the first clutchand the second clutch, a forward fifth speed results from engaging thesecond clutch and setting a state in which the reduced rotation isoutput from the reduced rotation output unit, a forward sixth speed isachieved on the basis of engagement of the second clutch and the secondbrake, and a backward first speed results from engaging the third brakeand setting a state in which the reduced rotation is output from thereduced rotation output unit, respectively.

[0084] As a result, the configuration can realize the six forward speedsand the one backward speed. Because both the first and second clutchesare engaged in the forward fourth speed, that is, the directly connectedstate is achieved in the forward fourth speed, it is possible to set agear ratio in the forward fifth speed and the forward sixth speed sothat is high. In the case, in particular, of a vehicle running at a highspeed for which mounting has been executed, it is possible to make theengine speed low, and it is possible to contribute to quietness of thevehicle when running at high speed.

[0085] In a variation of the planetary gear unit of the invention, theplanetary gear unit is configured from a first simple planetary gearhaving a second sun gear, a second carrier and a second ring gear, and asecond simple planetary gear having a third sun gear, a third carrierand a third ring gear. The first rotation element is configured from thethird ring gear which inputs the output rotation of the double pinionplanetary gear and which is selectively fixable on the basis ofengagement of the second brake, the second rotation element isconfigured from the second ring gear and the third carrier which isselectively fixable on the basis of engagement of the third brake andwhich inputs the rotation of the input shaft on the basis of engagementof the first clutch, the third rotation element is configured from thethird sun gear and the second sun gear which inputs the rotation of theinput shaft on the basis of engagement of the second clutch, and thefourth rotation element is configured from the second carrier whichmeshes with the second sun gear and the second ring gear.

[0086] As a result, it is possible to position the reduced rotationoutput unit and the planetary gear unit close to each other while it isalso possible to achieve, for example, the six forward speeds and theone backward speed. Further, it is possible to make the member thattransmits the reduced rotation comparatively short.

[0087] In this variation of the invention, the configuration is providedwith a first one-way clutch which is arranged in parallel to the thirdbrake and which restricts the rotation of the third carrier and thesecond ring gear to one direction. As a result, the configuration isable to achieve the forward first speed, for example, at a time ofnormal running on the basis of engagement of the second clutch and thefirst one-way clutch. Accordingly, it is possible to smoothly achievethe forward first speed, for example, at a time of changing from anon-running range to a running range.

[0088] Further, in this variation of the invention, the configuration issuch that the third brake and the first one-way clutch are arranged atan outer peripheral side of the planetary gear unit. As a result, it ispossible to position the output member close to, for example, the torqueconverter (because the portion where the first and second clutches arearranged can be made compact in the axial direction in comparison withthe case, for example, where the first one-way clutch is positionedadjacent to the second clutch). Accordingly, it is possible to make thedriven wheel transmission mechanism portion (in particular, the countershaft portion) compact in the axial direction.

[0089] In the variation of the invention, that configuration is suchthat an inner race of the first one-way clutch and the second ring gearare integrally formed. As a result, it is possible to make the automatictransmission compact, while at the same time it is possible to smoothlyachieve the forward first speed, for example, at a time of changing froma non-running range to a running range.

[0090] Also in this variation of the invention, the configurationincludes a second one-way clutch which is arranged in parallel to thesecond brake and which restricts the rotation of the third ring gear toone direction on the basis of engagement of the fourth brake. As aresult, it is possible to smoothly execute shifting, for example, fromthe forward second to the forward third.

[0091] As a result, the configuration makes it is possible to positionthe reduced rotation output unit and the planetary gear unit close toeach other while the six forward speeds and the one backward speed canbe achieved. Accordingly, it is possible to make the member thattransmits the reduced rotation comparatively short. Therefore, it ispossible to achieve a compact structure and weight saving in theautomatic transmission, and it is possible to make the inertia (theinertia force) small. Accordingly, it is possible to improve thecontrollability of the automatic transmission, and it is possible toreduce generation of shift shock.

[0092] In the variation of the invention, the configuration is such thata forward first speed is achieved on the basis of engagement of thesecond clutch and the third brake, a forward second speed is achieved onthe basis of engagement of the second clutch and the second brake, aforward third speed results from engaging the second clutch and settinga state in which reduced rotation is output from the reduced rotationoutput unit, a forward fourth speed is achieved on the basis ofengagement of the first clutch and the second clutch, a forward fifthspeed results from engaging the first clutch and setting a state inwhich reduced rotation is output from the reduced rotation output unit,a forward sixth speed is achieved on the basis of engagement of thefirst clutch and the second brake, and a backward first speed resultsfrom engaging the third brake and setting a state in which reducedrotation is output from the reduced rotation output unit, respectively.

[0093] As a result, the configuration can realize the six forward speedsand the one backward speed. Because both the first and second clutchesare engaged with the forward fourth speed, that is, the directlyconnected state is achieved in the forward fourth speed, it is possibleto set a gear ratio in the forward fifth speed and the forward sixthspeed so that it is high; in the case, in particular, of a vehiclerunning at a high speed for which mounting has been executed, it ispossible to make the engine speed low, and it is possible to contributeto the quietness of the vehicle when running at high speed.

[0094] In a further variation of the invention, the planetary gear unitcan be a Ravigneaux type planetary gear configured from a second sungear, a third sun gear, a second carrier and a second ring gear. Thefirst rotation element is configured from the third sun gear which iscapable of inputting the output rotation of the reduced rotation outputunit, the second rotation element is configured from the second carrierwhich has a long pinion engaged with the second sun gear and a shortpinion engaged with the third sun gear, which is selectively fixable onthe basis of engagement of the second brake, and which inputs therotation of the input shaft on the basis of engagement of the firstclutch, the third rotation element is configured from the second sungear which inputs the rotation of the input shaft on the basis ofengagement of the second clutch and which is selectively fixable on thebasis of engagement of the third brake, and the fourth rotation elementis configured from the second ring gear which meshes with the longpinion.

[0095] As a result, it is possible to position the reduced rotationoutput unit and the planetary gear unit close to each other while it ispossible to achieve, for example, the six forward speeds and the onebackward speed. Further, it is possible to make the member thattransmits the reduced rotation comparatively short.

[0096] In this further variation of the invention, the configurationincludes a first one-way clutch for restricting the rotation of thesecond carrier to one direction which is provided in parallel to thesecond brake. As a result, it is possible to achieve, for example, aforward first speed state at a time of normal running on the basis ofengagement of the third clutch and the first one-way clutch.Accordingly, it is possible to smoothly achieve the forward first speed,for example, at a time of changing from a non-running range to a runningrange.

[0097] Also, in this further variation of the invention, theconfiguration is such that the second brake and the first one-way clutchare arranged at an outer peripheral side of the planetary gear unit. Asa result, it is possible to position the output member close to, forexample, the torque converter (because the portion where the first andsecond clutches are arranged can be made compact in the axial directionin comparison with the case, for example, where the first one-way clutchis arranged adjacent to the first clutch). Accordingly, it is possibleto make the driven wheel transmission mechanism portion (in particular,the counter shaft portion) compact in the axial direction.

[0098] As a result, the configuration makes it is possible to positionthe reduced rotation output unit and the planetary gear unit close toeach other while the six forward speeds and the one backward speed canbe achieved. Accordingly, it is possible to make the member thattransmits the reduced rotation comparatively short. Therefore, it ispossible to achieve a compact structure and weight saving of theautomatic transmission, and it is possible to make the inertia (theinertia force) small. Therefore, it is possible to improve thecontrollability of the automatic transmission, and it is possible toreduce the generation of shift shock.

[0099] Additionally, in the further variation of the invention, theconfiguration is such that a forward first speed results from engagingthe second brake and setting a state in which reduced rotation is outputfrom the reduced rotation output unit, a forward second speed resultsfrom engaging the third brake and setting a state in which reducedrotation is output from the reduced rotation output unit, a forwardthird speed results from engaging the second clutch and setting a statein which reduced rotation is output from the reduced rotation outputunit, a forward fourth speed results from engaging the first clutch andsetting a state in which reduced rotation is output from the reducedrotation output unit, a forward fifth speed is achieved on the basis ofengagement of the first clutch and the second clutch, a forward sixthspeed is achieved on the basis of engagement of the first clutch and thethird brake, and a backward first speed is achieved on the basis ofengagement of the second clutch and the second brake, respectively.

[0100] As a result, the configuration can realize the six forward speedsand the one backward speed. Because the first and second clutches areengaged in the forward fifth speed, that is, the directly connectedstate is achieved, it is possible to output the reduced rotationthroughout the four shift speeds from the forward first speed to theforward fourth speed. It is also possible to execute finelydifferentiated shifting in a low middle speed range of the vehicle.Accordingly, in particular, in the low middle speed range of thevehicle, it is possible to fully use the rotation speed range so as torealize maximum efficiency of the drive power source, for example, theengine, or the like. Accordingly, it is possible to promote improvedfuel consumption. Further, because the directly connected state isachieved in the forward fifth speed, it is possible to set only theforward sixth speed as overdrive, and it is possible to make a finalgear ratio small in comparison with an automatic transmission, forexample, in which the directly connected state is achieved in theforward fourth speed, and the forward fifth speed and the forward sixthspeed constitute overdrive. Therefore, for example, it is possible tomake the diameter of the differential ring gear of the differentialportion small and, thus, it is possible to shorten the distance betweenthe input shaft and the shaft of the differential portion. Inparticular, in the case that the automatic transmission is mounted in anFF vehicle, it is possible to make the automatic transmission compact.

[0101] Lastly, in the invention, the driven wheel transmission mechanismhas a differential portion that outputs rotation to the driven wheel,and a counter shaft portion that engages with the differential portion.Further, the output member is configured from a counter gear engagedwith the counter shaft portion. As a result, it is possible to mount theautomatic transmission, for example, in a FF vehicle.

[0102] A description will be given below of a first embodiment accordingto the invention with reference to FIGS. 1 to 5.

[0103] An automatic transmission 1 ₁ in accordance with the firstembodiment of the invention is preferably used, in particular, for avehicle having a FF (front engine and front drive) structure, and has acase 3 formed from a housing case 3 a and a transmission case 3 b isshown in FIG. 1. A torque converter 12 is arranged within the housingcase 3 a, and an automatic speed change mechanism 2 ₁, a counter shaftportion (a driven wheel transmission mechanism) 4 and a differentialportion (a driven wheel transmission mechanism) 5 are arranged withinthe transmission case 3 b. The torque converter 12 is arranged on anaxis that centers on an input shaft 20 of the automatic speed changemechanism 2 ₁ that is coaxial with an output shaft 10, for example, ofan engine (not shown). The automatic speed change mechanism 2 ₁ isarranged on an axis that centers on the output shaft 10 of the engine,that is, a center shaft 30 that is coaxial with the input shaft 20.Further, the counter shaft portion 4 is arranged on a counter shaft 52that is parallel to the input shaft 20 and the center shaft 30, and thedifferential portion 5 is arranged on a shaft that is parallel to thecounter shaft 52 in such a manner as to have left and right vehicleaxles (not shown).

[0104] Note that the cross sectional development view shown in FIG. 1shows the automatic transmission 1 ₁ when expanded across a plane. Theinput shaft 20, the center shaft 30, the counter shaft 52 and the rightand left axles (not shown) are arranged so as to have a positionalrelationship resembling a “<” when viewed from the side. In particular,reference numeral 12′ in FIG. 1 shows the positional relationship of thetorque converter with respect to the counter shaft 52.

[0105] A disc-shaped member 11 is attached to the output shaft 10 of theengine described above, and an outer peripheral side of the disc-shapedmember 11 is connected to a pump impeller 12 a of the torque converter12. Further, a turbine runner 12 b of the torque converter 12 isconnected at an inner peripheral side thereof to a damper apparatus 13that absorbs torque fluctuation. An outer peripheral side of the damperapparatus 13 is connected to a piston member 14 of a lockup clutch whichcan be selectively engaged with the pump impeller 12 a and the pistonmember 14 is connected to the input shaft 20 of the automatic speedchange mechanism 2 ₁. In other words, in a state in which the pistonmember 14 is not engaged with the pump impeller 12 a, the torque of theengine (not shown) is transmitted to the input shaft 20 via the torqueconverter 12, and in a state in which the piston member 14 meshes withthe pump impeller 12 a, the output shaft 10 and the input shaft 20 arein a directly coupled state. In the directly coupled state the torque ofthe engine is directly transmitted to the input shaft 20.

[0106] Next, a description will be given of the automatic transmission 2₁ with reference to FIG. 2. As shown in FIG. 2, a spline 20 s is formedin an inner peripheral side of one end of the input shaft 20, that is,the one end is at the opposite side to the torque converter 12, and isengaged with a spline 30 s formed in an outer peripheral side of one endof the center shaft 30. Thus, the input shaft 20 and the center shaft 30are connected in a rotation direction. A planetary gear unit PU and aplanetary gear (a reduced rotation output unit, a speed reductionplanetary gear) PR are provided on the center shaft 30. The planetarygear unit PU has four rotation elements, namely, a sun gear (a secondrotation element, a third sun gear) S2, a carrier (a third rotationelement, a second carrier) CR2, a ring gear (a fourth rotation element,a second ring gear) R2, and a sun gear (a first rotation element, asecond sun gear) S3, and is a so-called Ravigneaux planetary gear. Thecarrier CR2 is provided with, in an intermeshing manner, a long pinionPL which is supported by side plates 42 and 44 and which meshes with thesun gear S3 and the ring gear R2, and a short pinion PS which issupported by side plates 43 and 44 and which meshes with the sun gearS2. Further, the planetary gear PR is a so-called double pinionplanetary gear in which a carrier (an input rotation element, a firstcarrier) CR1 is provide with, in an intermeshing manner, a pinion P1which is meshed with a ring gear R1 (an output rotation element, a firstring gear) and a pinion P2 which meshes with a sun gear (a fixedelement, a first sun gear) S1.

[0107] A multiple disc clutch (a first clutch) C1 having a hydraulicservo 62, a friction disk 72, a hub member 22 and a drum-like member 21which form a clutch drum (a first clutch drum), and a hub member (amember connected to the second rotation element) 23 connected to the sungear S2, is arranged at an inner peripheral side of the input shaft 20;and, a multiple disc clutch (a second clutch) C2, having a hydraulicservo 61 a, a friction disk 71, a drum-like member 24 and a cylindermember 61 e which form a clutch drum (a second clutch drum), and a hubmember 25 connected to the carrier CR2, is arranged at an outerperipheral side thereof.

[0108] The hydraulic servo 62 is configured from a piston member (afirst piston) 62 b that presses the friction disk 72, the drum-likemember 21 having a cylinder portion 62 e, an oil chamber (a firsthydraulic servo oil chamber) 62 a formed between the piston member 62 band the cylinder portion 62 e and sealed by sealing rings 62 f, 62 g, areturn spring 62 c that energizes the piston member 62 b in thedirection of the oil chamber 62 a, and a return plate 62 d that receivesthe energy of the return spring 62 c. The oil chamber 62 a communicateswith the oil passages 20 a, 20 b formed in the input shaft 20. The oilpassage 20 a extends to one end of the case 3, and communicates with anoil passage 91 of a boss portion 3 c that is provided on the input shaft20 such that it has a sleeve shape. Further, the oil passage 91communicates with a hydraulic control apparatus (not shown). In otherwords, because the hydraulic servo 62 is arranged on the input shaft 20,an oil passage from the hydraulic control apparatus (not shown) to theoil chamber 62 a is configured from a pair of sealing rings 81 that seala portion between the boss portion 3 c of the case 3 and the input shaft20.

[0109] Further, the hydraulic servo 61 is configured from a pistonmember (a second piston) 61 b that presses the friction disk 71, acylinder member 61 e, an oil chamber (a second hydraulic servo oilchamber) 61 a formed between the piston member 61 b and the cylindermember 61 e and sealed by sealing rings 61 f and 61 g, a return spring61 c that energizes the piston member 61 b in the direction of the oilchamber 61 a, and a return plate 61 d that receives the energy of thereturn spring 61 c. The oil chamber 61 a communicates with an oilpassage 92 in the boss portion 3 c, and the oil passage 92 communicateswith the hydraulic control apparatus (not shown). In other words, in thehydraulic servo 61, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 61 a is configured by a pair of sealingrings 80 that seal a portion between the boss portion 3 c of the case 3and the cylinder member 61 e.

[0110] In other words, the drum-like member 21 described above isconnected to the input shaft 20, and the drum-like member 22 isconnected to an outer peripheral side of the drum-like member 21. Theclutch C1, that can be selectively engaged by the hydraulic servo 62 ofthe clutch C1, is arranged at an inner peripheral side of a leading endportion of the hub member 22 so as to be spline engaged, and an innerperipheral side of the clutch C1 is connected to the hub member 23 so asto be spline engaged. Further, an inner peripheral side of the hubmember 23 is connected to one end of a sleeve member (member connectedto the second rotation element) 26 which is rotatably provided on thecenter shaft 30, and the sun gear S2 is integrally formed in an outerperipheral side of a leading end portion at the other end of the sleevemember 26.

[0111] Further, the clutch C2, that can be selectively engaged by thehydraulic servo 61 of the clutch C2, is arranged at an outer peripheralside of the leading end portion of the hub member 22 so as to be splineengaged, and a drum-like member 24 is connected to an outer peripheralside of the clutch C2 so as to be spline engaged at an inner peripheralside thereof. A one-way clutch (a first one-way clutch) F3 is positionedbetween the outer peripheral side of one end (the right side in thedrawing) of the drum-like member 24 and the transmission case 3 b,thereby restricting the rotation of the drum-like member 24 to onedirection. Further, a connection member 25 is connected using splineengagement to an inner peripheral side of the other end (the left sidein the drawing) of the drum-like member 24, and is connected to a sideplate 44 of the carrier CR2.

[0112] On the other hand, a multiple disc clutch (a third clutch, areduced rotation output unit) C3, having a hydraulic servo 66, afriction disk 76, a hub member 32 and a drum-like member 31 which form aclutch drum (a third clutch drum), and a hub member 33 connected to thecarrier CR1, is arranged on the center shaft 30. The hydraulic servo 66is configured from a piston member 66 b that presses the friction disk76, the drum-like member 31 having a cylinder portion 66 e, an oilchamber 66 a formed between the piston member 66 b and the cylinderportion 66 e and sealed by sealing rings 66 f, 66 g, a return spring 66c that energizes the piston member 66 b in the direction of the oilchamber 66 a, and a return plate 66 d that receives the energy of thereturn spring 66 c. In this case, the clutch drum, configured from thehub member 32 and the drum-like member 31, is open in the direction ofthe planetary gear PR, and the planetary gear PR is arranged between thehydraulic servo 66 and the planetary gear unit PU. Further, the frictiondisk 76 is arranged at a position at which it overlaps with theplanetary gear PR at an outer diameter side in a diametrical direction.

[0113] The oil chamber 66 a extends to the other end of the case 3opposite to the boss portion 3 c, and communicates with an oil passage93 of a boss portion 3 d provided on the center shaft 30 such that ithas a sleeve shape, and the oil passage 93 communicates with thehydraulic control apparatus (not shown). In other words, in thehydraulic servo 66, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 66 a is configured from a pair of sealingrings 82 sealing a portion between the boss portion 3 d of the case 3and the drum-like member 61 having the cylinder portion 66 e.

[0114] In other words, the drum-like member 31 is connected to thecenter shaft 30 at the opposite side (the left side in the drawing) tothe coupling with input shaft 20. The hub member 32 is connected to anouter peripheral side of the drum-like member 31. The clutch C3, thatcan be selectively engaged by the hydraulic servo 66 of the clutch C3,is arranged at an inner peripheral side of the leading end of the hubmember 32 so as to be spline engaged, and an extension portion of theside plate 33 of the carrier CR1 is arranged at an inner peripheral sideof the clutch C3 so as to be spline engaged. The carrier CR1 has thepinion P1 and the pinion P2 supported by the side plate 33 and a sideplate 34, and the pinion P2 is meshed with the sun gear S1 formed in asleeve shape and rotatably arranged on an axis. A hub member 35 isconnected to one end of the sun gear S1, and a multiple disc brake (afirst brake) B1 which can be selectively engaged by the hydraulic servo65 and which has a hydraulic servo 65 for the brake B1 and the frictiondisk 75 is disposed such that the friction disk 75 is spline engaged atan outer peripheral side of the hub member 35. Further, an outerperipheral side of the friction disk 75 of the brake B1 is splineengaged to a spline 3 s formed in an inner peripheral side of thetransmission case 3 b.

[0115] Further, the pinion P1 meshes with the ring gear R1 as describedabove, and a transmission member (a reduced rotation output unit) 40 ₁which is rotatably supported on the center shaft 30 and which transmitsa rotation of the ring gear R1 is connected to one end of the ring gearR1 at an inner peripheral side. A spline 40 s is formed in an outerperipheral side at the opposite side (the right side in the drawing) toa portion connected to the ring gear R1 of the transmission member 40 ₁.A hub member 46 (at the left center of the drawing) and a sleeve 41 ₁(to the right side of the hub member 46) are spline engaged to thespline 40 s.

[0116] A brake (a second brake) B2, which has a hydraulic servo 64 forthe brake B2 and a friction disk 74 and which can be selectively engagedby the hydraulic servo 64, is disposed such that the friction disk 74 isspline engaged at an outer peripheral side of the hub member 46. Anouter peripheral side of the friction disk 74 of the brake B2 is splineengaged to the spline 3 s formed in the inner peripheral side of thetransmission case 3 b, in the same manner as the brake B1.

[0117] The sun gear S3 of the planetary gear unit PU is integrallyformed in an inner peripheral side of the sleeve member 41 ₁, and thelong pinion PL, supported by the side plate 42 and the side plate 44 ofthe carrier CR2 as described above, meshes with the sun gear S1.Further, the short pinion PS is supported as described above between theside plate 44 and the side plate 43, and the hub member 47 is connectedto an outer peripheral side of the side plate 43. A brake (a thirdbrake) B4, which has a hydraulic servo 63 for the brake B4 and afriction disk 73 and which can be selectively engaged by the hydraulicservo 63 for the brake B4, is disposed at an outer peripheral side ofthe hub member 47 such that the friction disk 73 is spline engaged. Anouter peripheral side of the friction disk 73 in the brake B4 is splineengaged to the spline 3 s formed in the inner peripheral side of thetransmission case 3 b in the same manner as the brake B1 and the brakeB2.

[0118] Further, the ring gear R2 meshes with the long pinion PL asdescribed above, a connection member 45 is connected to one end of thering gear R2, and the ring gear R2 is connected to a counter gear 50 viathe connection member 45. A gear 51 fixed onto a counter shaft 52 of thecounter shaft portion 4 meshes with the counter gear 50, as shown inFIG. 1, and a gear 53 of the differential portion 5 meshes with thecounter shaft 52 via a gear 52 a formed on an outer peripheral surface.Further, the gear 53 is fixed to the housing 54, and the housing 54 isconnected to left and right axles (not shown) via a differential gear55.

[0119] As described above, the clutch C1 and the clutch C2 are arrangedon the input shaft 20, and the counter gear 50, the planetary gear unitPU and the planetary gear PR are arranged on the center shaft 30, in theorder listed. In other words, the planetary gear PR is arranged at oneside of the planetary gear unit PU in an axial direction, the clutch C1and the clutch C2 are arranged at the other side in the axial direction,and the counter gear 50 is arranged between the clutch C1, the clutch C2and the planetary gear unit PU. Further, the clutch C3 and the brake B1are arranged at the outer peripheral side of the planetary gear PR, andthe brake B2 and the brake B4 are arranged at the outer peripheral sideof the planetary gear unit PU, respectively. Further, the planetary gearPR, the planetary gear unit PU and the counter gear 50 are providedcoaxially with the input shaft 20.

[0120] Next, a description will be given of an operation of theautomatic transmission 1 ₁ with reference to FIGS. 3, 4 and 5 on thebasis of the structure described above. It should be noted that, in thevelocity diagram shown in FIG. 5, the vertical axis indicates a rotationspeed of each of the rotation elements, and the horizontal axisindicates and corresponds to a gear ratio of each of the rotationelements. Further, in the portion for the planetary gear unit PU in thevelocity diagram, the vertical axis of the endmost portion in thehorizontal direction (the right side in FIG. 5) corresponds to the sungear S3, and from there toward the left side of the drawing, thevertical axes correspond to the carrier CR2, the ring gear R2 and thesun gear S2, in that order.

[0121] As shown in FIG. 3, the rotation of the input shaft 20 is inputto the sun gear S2 with the engagement of the clutch C1. The rotation ofthe input shaft 20 is input to the carrier CR2 with the engagement ofthe clutch C2, and the rotation of the carrier CR2 is selectivelyfixable through engagement of the brake B4, and can be restricted to onedirection by the one-way clutch F3.

[0122] On the other hand, the rotation of the input shaft 20 is input tothe carrier CR1 with the engagement of the clutch C3, and the rotationof the sun gear S1 is selectively fixable with the engagement of thebrake B1. The ring gear R1 is connected to the sun gear S3 by thetransmission member 40 ₁ and the sleeve member 41 ₁, and the rotation ofthe ring gear R1 and the sun gear S3 is selectively fixable with theengagement of the brake B2. Further, the rotation of the ring gear R2 isoutput to the counter gear 50, and is output to driven wheels (notshown) via the counter gear 50, the counter shaft portion 4 and thedifferential portion 5(refer to FIG. 1).

[0123] In a forward first speed in a drive (D) range, as shown in FIG.4, the clutch C1 and the one-way clutch F3 are engaged. Accordingly, asshown in FIG. 5, the rotation of the input shaft 20 is input to the sungear S2 via the clutch C1, and the rotation of the carrier CR2 isrestricted to one direction (a forward rotation direction), that is, thecarrier CR2 is prevented from rotating backward, and is thereby in afixed state. Further, the rotation of the input shaft 20 input to thesun gear S2 is output to the ring gear R2 via the fixed carrier CR2, anda forward rotation that corresponds to the forward first speed is outputfrom the counter gear 50. In this case, in the planetary gear PRdescribed above, backward reduced rotation is output to the ring gear R1via the sun gear S3, and the sun gear S1 is fixed in accordance with theengagement of the brake B1. However, because the clutch C3 isdisengaged, the carrier CR1 is in an idle rotation state, and torque isnot transmitted. Further, when engine brake (coasting) takes place, theforward first speed state is maintained such that the brake B4 isengaged so as to fix the carrier CR2, and prevent the carrier CR2 fromrotating forward.

[0124] Note that, in the forward first speed, because the one-way clutchF3 prevents the carrier CR2 from rotating backward and allows it torotate forward, it is possible to smoothly achieve the forward firstspeed, for example, at a time of changing from a non-running range to arunning range as a result of automatic engagement of the one-way clutch.Further, the one-way clutch F3 is structured such that it receives therotation of the input shaft 20 via the sun gear S2; accordingly, anapplied torque is smaller, for example, in comparison with the case ofreceiving the reduced rotation, and thus it is not necessary to make theone-way clutch F3 and the drum-like member 24, connecting the one-wayclutch F3 and the clutch C2, large.

[0125] In a forward second speed in the drive (D) range, as shown inFIG. 4, the clutch C1 is engaged, and the brake B2 is engaged.Accordingly, as shown in FIG. 5, the rotation of the input shaft 20 isinput to the sun gear S2 via the clutch C1, and the sun gear S3 is fixedin accordance with the engagement of the brake B2. Thus, the carrier CR2rotates at a slightly reduced speed, the rotation input to the sun gearS2 is output to the ring gear R2 via the carrier CR2 that rotates atreduced speed, and a forward rotation that corresponds to the forwardsecond speed is output from the counter gear 50. In this case, at thistime, in the planetary gear PR described above, the sun gear S3 and thering gear R1 are fixed in accordance with the engagement of the brakeB2, and the clutch C3 is disengaged. Accordingly, the carrier CR1 andthe sun gear S1 are in a stopped state.

[0126] In a forward third speed in the drive (D) range, as shown in FIG.4, the clutch C1 and the clutch C3 are engaged, and the brake B1 isengaged. Accordingly, as shown in FIG. 5, the rotation of the inputshaft 20 is input to the carrier CR1 via the clutch C3, and to the sungear S2 via the clutch C1, and the sun gear S1 is fixed in accordancewith the engagement of the brake B1. Thus, the ring gear R1 rotates at areduced speed in accordance with the rotation of the input shaft 20input to the carrier CR1 and the fixed sun gear S1, and then the reducedrotation is output to the sun gear S3 via the transmission member 40 ₁and the sleeve member 41 ₁. Thus, the carrier CR2 rotates at a reducedrotation that is slightly larger than the reduced rotation of the sungear S3 in accordance with the rotation of the input shaft 20 input tothe sun gear S2, and the reduced rotation of the sun gear S3. Further,the rotation of the input shaft 20 input to the sun gear S2 is output tothe ring gear R2 via the carrier CR2 rotating at the reduced rotation,and a forward rotation that corresponds to the forward third speed isoutput from the counter gear 50. In this case, at this time, because thesun gear S3 and the ring gear R1 rotate at the reduced speed, thetransmission member 40 ₁ and the sleeve member 41 ₁ transmit acomparatively large torque.

[0127] In a forward fourth speed in the drive (D) range, as shown inFIG. 4, the clutch C1 and the clutch C2 are engaged. Accordingly, asshown in FIG. 5, the rotation of the input shaft 20 is input to the sungear S2 via the clutch C1 and to the carrier CR2 via the clutch C2.Thus, the rotation of the input shaft 20 is output as it is to the ringgear R2 in accordance with the rotation of the input shaft 20 input tothe sun gear S2 and the rotation of the input shaft 20 input to thecarrier CR2, that is, in a direct drive state. Accordingly, a forwardrotation that corresponds to the forward fourth speed is output from thecounter gear 50. In this case, at this time, in the planetary gear PR,the rotation of the input shaft 20 is input to the carrier CR1 via theclutch C3, and the rotation of the input shaft 20 (the direct driverotation) is input to the ring gear R1 from the sun gear S3. However,because the brake B1 is disconnected and the sun gear S1 is in theslipping state, torque transmission does not occur.

[0128] In a forward fifth speed in the drive (D) range, as shown in FIG.4, the clutch C2 and the clutch C3 are engaged, and the brake B1 isengaged. Accordingly, as shown in FIG. 5, the rotation of the inputshaft 20 is input to the carrier CR1 via the clutch C3 and to thecarrier CR2 via the clutch C2, and the sun gear S1 is fixed inaccordance with the engagement of the brake B1. Thus, the ring gear R1rotates at a reduced speed in accordance with the rotation of the inputshaft 20 input to the carrier CR1 and the fixed sun gear S1, and thereduced rotation is output to the sun gear S3 via the transmissionmember 40 ₁ and the sleeve member 41 ₁. The reduced rotation is outputto the ring gear R2 as an increased rotation in accordance with thereduced rotation of the sun gear S3 and the carrier CR2 to which therotation of the input shaft 20 is input, and a forward rotation thatcorresponds to the forward fifth speed is output from the counter gear50. In this case, at this time, because the sun gear S3 and the ringgear R1 rotate at the reduced speed in the same manner as the forwardthird speed state described above, the transmission member 40 ₁ and thesleeve member 41 ₁ transmit a comparatively large torque.

[0129] In a forward sixth speed in the drive (D) range, as shown in FIG.4, the clutch C2 is engaged, and the brake B2 is engaged. Accordingly,as shown in FIG. 5, the rotation of the input shaft 20 is input to thecarrier CR2 via the clutch C2, and the sun gear S3 is fixed inaccordance with the engagement of the brake B2. Thus, the rotationbecomes an increased rotation (larger than the forward fifth speeddescribed above) in accordance with the rotation of the input shaft 20input to the carrier CR2 and the fixed sun gear S2, and the increasedrotation is output to the ring gear R2. Accordingly, a forward rotationthat corresponds to the forward sixth speed is output from the countergear 50. In this case, at this time, in the planetary gear PR, becausethe sun gear S3 and the ring gear R1 are fixed in accordance with theengagement of the brake B2 in the same manner as the forward secondspeed state described above, and the clutch C3 is disengaged, thecarrier CR1 and the sun gear S1 are in a stopped state.

[0130] In a backward first speed in a reverse (R) range, as shown inFIG. 4, the clutch C3 is engaged, and the brakes B1, B4 are engaged.Accordingly, as shown in FIG. 5, the rotation of the input shaft 20 isinput to the carrier CR1 via the clutch C3, the sun gear S1 is fixed inaccordance with the engagement of the brake B1, and the carrier CR2 isfixed in accordance with the engagement of the brake B4. Thus, the ringgear R1 rotates at a reduced speed in accordance with the rotation ofthe input shaft 20 input to the carrier CR1, and the fixed sun gear S1,and the reduced rotation is output to the sun gear S3 via thetransmission member 401 and the sleeve member 41 ₁. Accordingly, therotation is output as a reduced rotation to the ring gear R2 inaccordance with the reduced rotation of the sun gear S3 and the fixedcarrier CR2, and a reverse rotation that corresponds to the backwardfirst speed is output from the counter gear 50. In this case, at thistime, because the sun gear S3 and the ring gear R1 rotate at the reducedspeed in the same manner as in the forward third speed and the forwardfifth speed state, the transmission member 40 ₁ and the sleeve member 41₁ transmit a comparatively large torque.

[0131] Further, at this time, the brake B4 is structured such that itreceives the rotation of the sun gear S3 to which reduced rotation isinput. However, because the brake B4 is arranged comparatively close tothe outer peripheral side of the planetary gear unit PU, it is possibleto make the hub member 47, that transmits the torque on the basis of thereduced rotation, comparatively short.

[0132] In a parking (P) range and a neutral (N) range, in particular,the clutch C1, the clutch C2 and the clutch C3 are disengaged, and powertransmission between the input shaft 20 and the counter gear 50 is in aninterrupted state, such that the entire automatic transmission 2 ₁ is ina slipping state (a neutral state). In this case, the brake B1 fixingthe sun gear S1 is engaged; this prevents frequent repetition ofengagement and disengagement of the brake B1, but does not have anyparticular influence on the rotation state of the other rotationelements within the automatic speed change mechanism 2 ₁.

[0133] In this case, in the automatic transmission 1 ₁ described above,the clutch C3 is engaged as in the state of the forward third speed, theforward fifth speed and the backward first speed as described above, andinputs the rotation of the input shaft 20 to the carrier CR1. However,the invention is not limited to this, and the clutch C3 may beinterposed between the ring gear R1 and the sun gear S3; the carrier CR1may be placed in a constantly connected state with the input shaft 20;and the clutch C3 may be engaged in the same state as the forward thirdspeed, the forward fifth speed and the backward first speed. Even so, inthe same manner, it is possible to output the reduced rotation to thesun gear S3 by the planetary gear PR, the clutch C3 and the transmissionmember 40 ₁, and it is possible to obtain the forward sixth speed andthe backward first speed in the same manner. However, because the clutchC3, in this case, is such that it connects and disconnects the reducedrotation, and it is necessary to connect and disconnect a greater torquethan when connecting and disconnecting the rotation of the input shaft20 in the embodiment described above, it is necessary to make the clutchC3 comparatively large.

[0134] As described above, in accordance with the automatic transmission1 ₁ according to the invention, the planetary gear PR, the clutch C3 andthe transmission member 40 ₁ which correspond to the reduced rotationoutput unit are arranged at one side (the left side in FIGS. 1, 2 and 3)in the axial direction of the planetary gear unit PU, the clutch C1 andthe clutch C2 are arranged at the other side (the right side in FIGS. 1,2 and 3) in the axial direction of the planetary gear unit PU, and thecounter gear 50, that corresponds to the output member, is arrangedbetween the clutch C1, the clutch C2 and the planetary gear unit PU.Accordingly, it is possible to position, in particular, the planetarygear PR and the planetary gear unit PU close to each other, and it ispossible to make the axial length of the transmission member 40 ₁ andthe sleeve member 41 ₁, that transmits the reduced rotation,comparatively short. Accordingly, because it is possible to achieve acompact structure and weight saving of the automatic transmission 1 ₁,and it is possible to make the inertia (the inertia force) small inaccordance with the weight saving of the transmission member 40 ₁ andthe sleeve member 41 ₁, it is possible to improve the controllability ofthe automatic transmission 1 ₁. Further, it is possible to reduce thegeneration of shift shock.

[0135] Because the clutch C2 is connected to the carrier CR2 via theouter peripheral side of the clutch C1, it is possible to prevent themember that connects each of the rotation elements from beingcomplicated, and it is possible to make the automatic transmission 1 ₁compact.

[0136] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof, and thus, can not haveits diameter enlarged toward the outer peripheral side. However, it ispossible to ensure that the hydraulic servo 62, and more particularly,the pressure receiving area of the oil chamber 62 a for the hydraulicservo 62, is large at the inner peripheral side by providing thehydraulic servo 62 on the input shaft 20 (in comparison with the case,for example, that the hydraulic servo 62 is provided on the boss portion3 c), and it is possible to increase the capacity of the clutch C1.

[0137] Further, the planetary gear PR, the planetary gear unit PU andthe counter gear 50 are provided coaxially with the input shaft 20.Accordingly, it is possible to make the driven wheel transmissionmechanism (for example, the counter shaft portion 4, or the like)compact, particularly in the case that the automatic transmission 1 ₁ ismounted in the FF vehicle (for example, in comparison with the case whenthe speed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and it is possible to improve ease of vehiclemounting of the automatic transmission 1 ₁.

[0138] Further, for example, as disclosed in Japanese Patent Laid-OpenPublication No. 2001-263438, in the case that the clutch C3 isinterposed between the ring gear R1 and the sun gear S3, it is necessaryto connect and disconnect the reduced rotation, so that the structurebecomes comparatively large, and the distance between the planetary gearPR and the planetary gear unit PU is lengthened. However, as a result ofinterposition between the input shaft 20 and the carrier CR1, thereduced rotation output from the ring gear R1 of the planetary gear PRis connected and disconnected by connecting and disconnecting therotation of the input shaft 20 by using the clutch C3. Thus, it ispossible to make the clutch C3 compact, and it is possible to arrangethe planetary gear PR and the planetary gear unit PU at comparativelyclose positions. Therefore, it is possible to make the automatictransmission 1 ₁ compact.

[0139] Further, because the hydraulic servo 62 is provided on the inputshaft 20, it is possible to supply oil to the oil chamber 62 a of thehydraulic servo 62 by preventing the oil leaking from the case 3 usingthe pair of sealing rings 81, and supplying the oil to the oil passages20 a, 20 b provided within the input shaft 20, for example, withoutproviding a sealing ring between the input shaft 20 and the hydraulicservo 62. Further, the hydraulic servos 61, 66 can supply the oil fromthe boss portions 3 c, 3 d that respectively extend from the case 3, forexample, without passing it through other members. That is, the oil canbe supplied by respectively arranging the pair of sealing rings 80, 82.Accordingly, it is possible to supply the oil to the hydraulic servos62, 61, 66 by simply respectively arranging the pairs of sealing rings81, 80, 82, and it is possible to minimize the sliding resistanceresulting from the sealing rings, whereby it is possible to improve theefficiency of the automatic transmission 1 ₁.

[0140] Further, because the friction disk 33 is arranged at an outerperipheral side of the planetary gear PR in the diametrical direction,it is possible to make the automatic transmission 1 ₁ compact in theaxial direction. As it is possible to arrange the planetary gear PR andthe planetary gear unit PU adjacent to each other by arranging theplanetary gear PR between the hydraulic servo 66 of the clutch C3 andthe planetary gear unit PU in the axial direction (because the hydraulicservo 66 of the clutch C3 is not provided between the planetary gear PRand the planetary gear unit PU), it is possible to make the transmissionmember 40 ₁ and the sleeve member 41 ₁ comparatively short. Accordingly,because it is possible to achieve a compact structure and weight savingof the automatic transmission 1 ₁, and it is possible to make theinertia (the inertia force) small, it is possible to improve thecontrollability of the automatic transmission 1 ₁, and reduce thegeneration of shift shock.

[0141] Because the planetary gear PR is a double pinion planetary gear,it is possible to output the rotation of the input shaft 20 as reducedrotation. Further, even in the case that the gear ratio of the automatictransmission 1 ₁ is favorably set, high speed rotation can be restrictedwithout making each of the rotation elements of the planetary gear unitand the speed reduction planetary gear large. Accordingly, it ispossible to make the automatic transmission 1 ₁ compact.

[0142] As the configuration of the planetary gear PR is provided withthe carrier CR1, that is the input rotation element, the sun gear S1,that is the fixed element, and the ring gear R1, that is the outputrotation element, it is possible to output the rotation of the inputshaft 20 as the reduced rotation.

[0143] In addition, because the planetary gear unit PU is a Ravigneauxtype planetary gear configured from the sun gear S2, the sun gear S3,the carrier CR2 and the ring gear R2, it is possible to arrange theplanetary gear PR and the planetary gear unit PU close to each other,while at the same it is possible to achieve, for example, six forwardspeeds and one backward speed. Accordingly, it is possible to make thetransmission member 40 ₁ and the sleeve member 41 ₁, that transmit thereduced rotation, comparatively short.

[0144] Additionally, as the one-way clutch F3 is provided in parallel tothe brake B4 so as to restrict the rotation of the carrier CR2 to onedirection, it is possible to achieve the forward first speed at a timeof normal running in accordance with the engagement of the clutch C1 andthe one-way clutch F3. Thus, it is possible to smoothly achieve theforward first speed, for example, at a time of changing from anon-running range to a running range.

[0145] Further, the brake B4 is arranged at the outer peripheral side ofthe planetary gear unit PU, and the one-way clutch F3 is arrangedadjacent to the clutch C2. Accordingly, while the one way clutch F3 isengaged with the clutch C1, that inputs the rotation of the input shaftat the time of realizing the forward first speed, the brake B4 is ableto achieve the backward first speed by being engaged with the clutch C3,that connects and disconnecting the reduced rotation. As a result, areaction force torque applied to the brake B4 becomes larger than areaction force torque applied to the one-way clutch F3. Accordingly, itis possible to make the hub member 47, that transmits the torqueresulting from the reduced rotation to the brake B4, comparatively shortby providing a brake B4 close to the outer peripheral side of theplanetary gear unit PU. Further, even in the case where the one-wayclutch F3 is provided close to the clutch C2 which is separate from theplanetary gear unit PU, it is not necessary to make the hub member 25,that connects the clutch C2 and the carrier CR2 and the side plate 44,large. Further, because the one-way clutch F3 is not arranged at theouter periphery of the planetary gear unit PU, it is possible to improvedesign freedom of the brake. Accordingly, it is possible to achieve acompact structure and weight saving of the automatic transmission 1 ₁.

[0146] Further, as shown in the velocity diagram, it is possible toarrange the planetary gear PR and the planetary gear unit PU close toeach other while achieving the six forward speeds and one backwardspeed, and it is possible to make the transmission member 40 ₁, thattransmits the reduced rotation, and the sleeve member 41 ₁ comparativelyshort. Accordingly, because it is possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₁, and it ispossible to make the inertia (the inertia force) small, it is possibleto improve the controllability of the automatic transmission 1 ₁ and itis possible to reduce the generation of shift shock.

[0147] Further, the configuration allows the six forward speeds and onebackward speed to be realized, and both the clutches C1, C2 are engagedin the forward fourth speed, that is, the directly connected state isestablished in the forward fourth speed. As a result, it is possible toset the gear ratio in the forward fifth speed and the forward sixthspeed so that it is high. In the case, in particular, of a vehiclerunning at a high speed for which mounting has been executed, it ispossible to make the engine speed low, and it is possible to contributeto quietness of the vehicle when running at high speed.

[0148] Further, because the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheels,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4, it is possible to mount the automatictransmission 1 ₁, for example, in the FF vehicle.

[0149] Hereinafter, a description will be given, with reference to FIGS.6 to 10, of a second embodiment that is a partial modification of thefirst embodiment. Note that, in the second embodiment, with theexception of partially modified portions, the same reference numeralsdenote the same elements as those of the first embodiment and adescription thereof will be omitted.

[0150] As shown in FIG. 6, an automatic transmission 1 ₂ in accordancewith the second embodiment, as compared to the automatic transmission 1₁ according to the first embodiment (refer to FIG. 1), is structuredsuch that a one-way clutch (a second one-way clutch) F2 is arrangedbetween the planetary gear unit PU and the planetary gear (the reducedrotation output unit, the speed reduction planetary gear) PR. A brake (afourth brake) B3 that connects and disconnects engagement of the one-wayclutch F2 is also provided.

[0151] As shown in FIG. 7, a transmission member 40 ₂ connected to thering gear R1 of the planetary gear PR is spline engaged to a sleevemember 41 ₂ with which the sun gear S3 of the planetary gear unit PU isintegrally formed. Further, an inner race of the one-way clutch F2 isintegrally formed in the sleeve member 41 ₂, and an outer race of theone-way clutch F2 is integrally formed with the hub member 48. A brake(a fourth brake) B3 which has a hydraulic servo 67 for the brake B3 anda friction disk 77, and which can be selectively engaged by thehydraulic servo 67 for the brake B3, is arranged at an outer peripheralside of the hub member 48 in such a manner that the friction disk 77 isspline engaged. Further, an outer peripheral side of the friction disk77 in the brake B3 is spline engaged to the spline 3 s formed in theinner peripheral side of the transmission case 3 b. Note that, the hubmember 46, that is spline engaged to the brake B2, is spline engaged tothe sleeve member 41 ₂ in an inner peripheral side thereof, that is, itis connected to the transmission member 40 ₂ via the sleeve member 41 ₂.

[0152] Next, a description will be given of operation of the one-wayclutch F2 of the automatic transmission 1 ₂ with reference to FIGS. 8, 9and 10 on the basis of the structure described above. It should be notedthat, in the same manner as the first embodiment, in the velocitydiagram shown in FIG. 10, the vertical axis indicates a rotation speedof each of the rotation elements, and the horizontal axis indicates andcorresponds to a gear ratio of each of the rotation elements. Further,in the portion for the planetary gear unit PU in the velocity diagram,the vertical axis of the endmost portion in the horizontal direction(the right side in FIG. 10) corresponds to the sun gear S3, and fromthere toward the left side of the drawing, the vertical axes correspondto the carrier CR2, the ring gear R2 and the sun gear S2, in that order.

[0153] As shown in FIG. 8, the one-way clutch F2 is arranged in parallelto the brake B2, and restricts the rotation of the ring gear R1 to onedirection (a forward rotation direction) via the sleeve member 41 ₂,that is, via the sun gear S3 and the transmission member 40 ₂, inaccordance with the engagement of the brake B3.

[0154] Accordingly, as shown in FIG. 9, in the forward second speed inthe drive (D) range, the clutch C1 is engaged, and the one-way clutch F2is engaged in accordance with the engagement of the brake B3.Accordingly, as shown in FIG. 10, the rotation of the input shaft 20 isinput to the sun gear S2 via the clutch C1, and the rotation of the sungear S3 is restricted to one direction (the forward rotation direction)by the one-way clutch F2 in accordance with the engagement of the brakeB3. Thus, the carrier CR2 rotates at a slightly reduced speed, therotation input to the sun gear S2 is output to the ring gear R2 via thecarrier CR2 with reduced rotation, and a forward rotation thatcorresponds to the forward second speed is output from the counter gear50. In this case, at this time, in the planetary gear PR describedabove, the sun gear S3 and the ring gear R1 are prevented from rotatingin reverse by the one-way clutch F2, and the clutch C3 is disengaged.Accordingly, the carrier CR1 and the sun gear S1 are in a stopped state.

[0155] In this case, the brake B3 is engaged and the one-way clutch F2prevents the sun gear S3 from rotating in reverse, whereby the sun gearS2 rotates forward and is automatically released by the one-way clutchF3 engaged in the forward first speed. Thus, shifting can be smoothlyexecuted from the forward first speed to the forward second speed, forexample, while preventing the engine from racing. Further, when enginebrake (at a time of coasting) takes place, the sun gear S3 (and the ringgear R1) is fixed by engagement of the brake B2 provided in parallelwith the one-way clutch F2, and the forward second speed state describedabove is maintained such that the sun gear S3 is prevented from rotatingforward.

[0156] As described above, with the automatic transmission 1 ₂ accordingto the invention, the planetary gear PR, the clutch C3 and thetransmission member 40 ₂ which correspond to the reduced rotation outputunit are arranged at one side (the left side in FIGS. 6, 7 and 8) in theaxial direction of the planetary gear unit PU; the clutch C1 and theclutch C2 are arranged at the other side (the right side in FIGS. 6, 7and 8) in the axial direction of the planetary gear unit PU; and thecounter gear 50, that corresponds to the output member, is arrangedbetween the clutch C1, the clutch C2 and the planetary gear unit PU. Asa result, it is possible, in particular, to arrange the planetary gearPR and the planetary gear unit PU at positions close to each other, andit is possible to make the axial direction length of the transmissionmember 40 ₂, that transmits the reduced rotation and the sleeve member41 ₂, comparatively short. Accordingly, it is possible to achieve acompact structure and weight saving of the automatic transmission 1 ₂,and it is possible to make the inertia (the inertia force) small as aresult of the weight saving of the transmission member 40 ₂ and thesleeve member 41 ₂. As a result, it is possible to improve thecontrollability of the automatic transmission 1 ₂, and it is possible toreduce the generation of shift shock.

[0157] Further, because the clutch C2 is connected to the carrier CR2via the outer peripheral side of the clutch C1, it is possible toprevent the member that connects each of the rotation elements frombeing complicated, and it is possible to make the automatic transmission1 ₂ compact.

[0158] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof, and can not have itsdiameter enlarged toward the outer peripheral side. However, it ispossible to ensure that the hydraulic servo 62 and, more particularly,the pressure receiving area of the oil chamber 62 a for the hydraulicservo 62, is large at the inner peripheral side by providing thehydraulic servo 62 on the input shaft 20 (in comparison with the case,for example, that the hydraulic servo 62 is provided on the boss portion3 c), and it is possible to increase the capacity of the clutch C1.

[0159] Further, the planetary gear PR, the planetary gear unit PU andthe counter gear 50 are provided coaxially with the input shaft 20.Accordingly, it is possible to make the driven wheel transmissionmechanism (for example, the counter shaft portion 4, or the like)compact, particularly in the case where the automatic transmission 1 ₂is mounted in the FF vehicle (for example, in comparison with the casewhen the speed reduction planetary gear, or the like, is provided onanother shaft). Thus, for example, it is possible to prevent the drivenwheel transmission mechanism from being interfered with by, for example,a vehicle body member, and it is possible to improve the ease of vehiclemounting of the automatic transmission 1 ₂.

[0160] Further, in the same manner as the first embodiment, in the casewhere the clutch C3 is interposed between the ring gear R1 and the sungear S3, it is necessary to connect and disconnect the reduced rotation.Thus, the structure becomes comparatively large, and the distancebetween the planetary gear PR and the planetary gear unit PU islengthened. However, because the reduced rotation output from the ringgear R1 of the planetary gear PR is connected and disconnected byconnecting and disconnecting the rotation of the input shaft 20 usingthe clutch C3, it is possible to make the clutch C3 compact, and it ispossible to arrange the planetary gear PR and the planetary gear unit PUat comparatively close positions. Therefore, it is possible to make theautomatic transmission 1 ₂ compact.

[0161] Further, because the hydraulic servo 62 is provided on the inputshaft 20, it is possible to supply the oil to the oil chamber 62 a ofthe hydraulic servo 62 by preventing the oil from leaking from the case3 using the pair of sealing rings 81 and supplying the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 62. Further, the hydraulic servos 61, 66 can supply theoil from the boss portions 3 c, 3 d that respectively extend from thecase 3, for example, without passing it through other members, that is,the oil can be supplied by respectively arranging the pair of sealingrings 80, 82. Accordingly, it is possible to supply the oil to thehydraulic servos 62, 61, 66 by simply arranging the pairs of respectivesealing rings 81, 80, 82, and it is possible to minimize the slidingresistance resulting from the sealing rings. As a result, it is possibleto improve the efficiency of the automatic transmission 1 ₂.

[0162] Further, because the friction disk 33 is arranged at an outerperipheral side of the planetary gear PR in the diametrical direction,it is possible to make the automatic transmission 1 ₂ compact in theaxial direction. Because it is possible to arrange the planetary gear PRand the planetary gear unit PU adjacent to each other by arranging theplanetary gear PR between the hydraulic servo 66 of the clutch C3 andthe planetary gear unit PU in the axial direction (as the hydraulicservo 66 of the clutch C3 is not provided between the planetary gear PRand the planetary gear unit PU), it is possible to make the transmissionmember 40 ₂ and the sleeve member 41 ₂ comparatively short. Accordingly,because it is possible to achieve a compact structure and weight savingof the automatic transmission 1 ₂, and it is possible to make theinertia (the inertia force) small, it is possible to improve thecontrollability of the automatic transmission 1 ₂, and it is possible toreduce the generation of shift shock.

[0163] In addition, because the planetary gear PR is the double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as a reduced rotation. Further, even in the case that the gear ratioof the automatic transmission 1 ₂ is favorably set, high speed rotationcan be restricted without making each of the rotation elements of theplanetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₂compact.

[0164] Additionally, as the configuration of the planetary gear PR isprovided with the carrier CR1, that corresponds to the input rotationelement, the sun gear S1, that corresponds to the fixed element, and thering gear R1, that corresponds to the output rotation element, it ispossible to output the rotation of the input shaft 20 as the reducedrotation.

[0165] Further, because the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2, it is possible to arrange theplanetary gear PR and the planetary gear unit PU close to each other,while at the same time it is possible to achieve, for example, sixforward speeds and one backward speed. Accordingly, it is possible tomake the transmission member 40 ₂ that transmits the reduced rotationand the sleeve member 41 ₂ comparatively short.

[0166] Because the one-way clutch F3 is provided in parallel to thebrake B4 and restricts the rotation of the carrier CR2 to one direction,it is possible to achieve the forward first speed at a time of normalrunning in accordance with the engagement of the clutch C1 and theone-way clutch F3. Thus, it is possible to smoothly achieve the forwardfirst speed, for example, at a time of changing from a non-running rangeto a running range. Further, the brake B4 is arranged at the outerperipheral side of the planetary gear unit PU, and the one-way clutch F3is arranged adjacent to the clutch C2. Accordingly, while the one wayclutch F3 is engaged with the clutch C1 that inputs the rotation of theinput shaft at the time of realizing the forward first speed, the brakeB4 is able to achieve the backward first speed by being engaged with theclutch C3 that connects and disconnects the reduced rotation. As aresult, the reaction force torque applied to the brake B4 becomes largerthan the reaction force torque applied to the one-way clutch F3.Accordingly, it is possible to make the hub member 47, that transmitsthe torque resulting from the reduced rotation to the brake B4,comparatively short, by providing a brake B4 close to the outerperipheral side of the planetary gear unit PU. Further, even in the casethat the one-way clutch F3 is provided close to the clutch C2 which isseparate from the planetary gear unit PU, it is not necessary to makethe hub member 25, that connects the clutch C2 and the carrier CR2 andthe side plate 44, large.

[0167] Further, because the one-way clutch F3 is not arranged at theouter periphery of the planetary gear unit PU, it is possible to improvedesign freedom of the brake. Accordingly, it is possible to achieve acompact structure and weight saving in the automatic transmission 1 ₂.

[0168] Moreover, because the one-way clutch F2 is provided in parallelto the brake B2 and restricts the rotation of the sun gear S3 to onedirection in accordance with the engagement of the brake B3, it ispossible to smoothly execute shifting from the forward second speed tothe forward third speed.

[0169] Further, the inner race of the one-way clutch F2 is integrallyformed with the sleeve member 41 ₂. Accordingly, it is possible to makethe automatic transmission 1 ₂ compact, particularly in the diametricaldirection, at the same time as being able to smoothly execute shiftingfrom the forward second speed to the forward third speed.

[0170] Further, as shown in the velocity diagram, it is possible toarrange the planetary gear PR and the planetary gear unit PU close toeach other while achieving the six forward speeds and the one backwardspeed, and it is possible to make the transmission member 40 ₂ thattransmits the reduced rotation and the sleeve member 41 ₂ comparativelyshort. Accordingly, as it is possible to achieve a compact structure andweight saving in the automatic transmission 1 ₂, and it is possible tomake the inertia (the inertia force) small, it is possible to improvethe controllability of the automatic transmission 1 ₂ and to reduce thegeneration of shift shock.

[0171] Further, the configuration allows the six forward speeds and theone backward speed to be realized, and both the clutches C1, C2 areengaged in the forward fourth speed, that is, the directly connectedstate is established in the forward fourth speed. As a result, it ispossible to set the gear ratio in the forward fifth speed and theforward sixth speed so that it is high. In the case, in particular, of avehicle running at a high speed for which mounting has been executed, itis possible to make the engine speed low, and it is possible tocontribute to quietness of the vehicle when running at high speed.

[0172] Also, because the driven wheel transmission mechanism has thedifferential portion 5 outputting the rotation to the driven wheel, thecounter shaft portion 4 that engages with the differential portion 5,and the output member that is the counter gear that engages with thecounter shaft portion 4, it is possible to mount the automatictransmission 1 ₂, for example, in the FF vehicle.

[0173] Hereinafter, a description will be given, with reference to FIGS.11 to 14, of a third embodiment that is a partial modification of thefirst and second embodiments. Note that, in the third embodiment, withthe exception of the partially modified portions, the same referencenumerals denote the same elements as those of the first embodiment and adescription thereof will be omitted.

[0174] As shown in FIG. 11, an automatic transmission 1 ₃ in accordancewith the third embodiment is such that the automatic speed changemechanism 2 of the automatic transmissions 1 ₁, 1 ₂, according to thefirst and second embodiments, is modified. An automatic speed changemechanism 2 ₃ is structured, in the same manner as the automatic speedchange mechanism 2 ₁, 2 ₂ according to the first and second embodiments,such that a spline 20 s, which is formed at an inner peripheral side ofthe input shaft 20 at the opposite end to the torque converter 12 (referto FIGS. 1 and 6), is engaged with a spline 30 s formed in an outerperipheral side of one end of a center shaft 30 ₃, that is, the inputshaft 20 and the center shaft 30 ₃ are connected in a rotationdirection. The planetary gear unit PU and the planetary gear (thereduced rotation output unit, the speed reduction planetary gear) PR areprovided on the center shaft 30 ₃.

[0175] The planetary gear unit PU is a so-called Simpson type planetarygear which is configured from a first simple planetary gear SP2 and asecond simple planet SP3. The planetary gear unit PU has, as fourrotation elements, a sun gear (a third rotation element, a second sungear) S2 and a sun gear (also a third rotation element, a third sungear) S3 which are connected via a sleeve 127 described below, a carrier(a second rotation element, a third carrier) CR3 and a ring gear (asecond rotation element, a second ring gear) R2 which are connected by aside plate 143, a ring gear (a first rotation element, a third ringgear) R3, and a carrier (a fourth rotation element, a second carrier)CR2. Further, the planetary gear PR is a so-called double pinionplanetary gear having a carrier (an input rotation element, a firstcarrier) CR1 that is provide with, in an intermeshing manner, a pinionP1 a which meshes with a ring gear R1 (an output rotation element, afirst ring gear) and a pinion P1 b which meshes with a sun gear (a fixedelement, a first sun gear) S1.

[0176] A multiple disc clutch (a second clutch) C1 having a cylindermember 161 e and a drum-like member 122 which form a hydraulic servo161, a friction disk 172 and a clutch drum (a second clutch drum), and ahub member (a member connected to the third rotation element) 125connected to the sleeve member 127, is arranged on the input shaft 20 atan outer peripheral side thereof. A multiple disc clutch (a firstclutch) C2 having a cylinder member 162 e and a drum-like member 124which form a hydraulic servo 162, a friction disk 171 and a clutch drum(a first clutch drum), and a hub member (a member connected to thesecond rotation member) 123 connected to a sleeve member 126 ₃, isarranged at an inner peripheral side thereof.

[0177] The hydraulic servo 161 is configured from a piston member (asecond piston) 161 b that presses the friction disk 172, a cylindermember 161 e that is spline engaged to a cylinder member 162 e describedbelow and to which the rotation of the input shaft 20 is input, an oilchamber (a second hydraulic servo oil pressure chamber) 161 a which isformed between the piston member 161 b and the cylinder member 161 e andwhich is sealed by sealing rings 161 f, 161 g, a return spring 161 cthat energizes the piston member 161 b in the direction of the oilchamber 161 a, and a return plate 161 d that receives the energy of thereturn spring 161 c. The oil chamber 161 a extends to one end of thecase 3, and communicates with an oil passage 192 of a boss portion (afirst boss portion) 3 c provided on the input shaft 20 such that it hasa sleeve shape. Further, the oil passage 192 communicates with thehydraulic control apparatus (not shown). In other words, in thehydraulic servo 161, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 161 a is configured from a pair ofsealing rings 80 that seal a portion between the boss portion 3 c of thecase 3 and the cylinder member 161 e.

[0178] Further, the hydraulic servo 162 is configured from a pistonmember (a first piston) 162 b, that presses the friction disk 171, acylinder member 162 e, that is firmly fixed to the input shaft 20, anoil chamber (a first hydraulic servo oil pressure chamber) 162 a whichis formed between the piston member 162 b and the cylinder member 162 eand which is sealed by sealing rings 162 f, 162 g, a return spring 162 cthat energizes the piston member 162 b in the direction of the oilchamber 162 a, and a return plate 162 d that receives the energy of thereturn spring 162 c. The oil chamber 162 a communicates with the oilpassages 20 a, 20 b formed in the input shaft 20, and the oil passage 20communicates with an oil passage 191 of the boss portion 3 c. Further,the oil passage 191 communicates with the hydraulic control apparatus(not shown). In other words, because the hydraulic servo 162 is arrangedon the input shaft 20, an oil passage from the hydraulic controlapparatus (not shown) to the oil chamber 162 a is configured from thepair of sealing rings 81 sealing a portion between the boss portion 3 cof the case 3 and the input shaft 20.

[0179] In other words, the cylinder member 161 e described above isconnected to the input shaft 20 via the cylinder member 162 e describedabove, and the drum-like member 122 is connected to an outer peripheralside of the cylinder member 161 e. The friction disk 172 of the clutchC1, that can be selectively engaged by the hydraulic servo 161 for theclutch C1, is positioned so as to be spline engaged at an innerperipheral side of a leading end portion of the drum-like member 122,and an inner peripheral side of the friction disk 172 of the clutch C1is connected by spline engagement to the hub member 125. Further, aninner peripheral side of the hub member 125 is connected to one end ofthe sleeve member 127 which is rotatably provided on the center shaft 30₃, and the sun gear S2 and the sun gear S3 are integrally formed in anouter peripheral side of the sleeve member 127.

[0180] Further, the drum-like member 124 is connected to an outerperipheral side of the cylinder member 162 e, the friction disk 171 ofthe clutch C2, that can be selectively engaged by the hydraulic servo162 for the clutch C2, is positioned so as to be spline engaged at aninner peripheral side of the leading end portion of the drum-like member124, and an inner peripheral side of the friction disk 171 of the clutchC2 is connected by spline engagement to the hub member 123. Further, aninner peripheral side of the hub member 123 is connected to one end ofthe sleeve member 126 rotatably provided on the center shaft 30 ₃, aspline 126 s is formed in an outer peripheral side of a leading endportion at the other end of the sleeve member 126, and a side plate 142₃ is connected via a spline 142 s of the side plate 142 ₃ of the carrierCR3.

[0181] On the other hand, provided on a boss portion (a second bossportion) 3 d ₃, which extends at the other end of the case 3 opposite tothe boss portion 3 c and which has a fixed sleeve-like member 131 ₃, isa multiple disc clutch (a reduced rotation output unit, a third clutch)C3 having a clutch drum (a third clutch drum) 132 including a hydraulicservo 166, a friction disk 176 and a cylinder portion 166 e. Thehydraulic servo 166 is configured from a piston member 166 b thatpresses the friction disk 176, an oil chamber 166 a which is formedbetween the piston member 166 b and the cylinder portion 166 e and issealed by sealing rings 166 f, 166 g, a return spring 166 c thatenergizes the piston member 166 b in the direction of the oil chamber166 a, and a return plate 166 d that receives the energy of the returnspring 166 c. Note that, the clutch drum 132 is open in the direction ofthe planetary gear PR, and the planetary gear PR is arranged between thehydraulic servo 166 and the planetary gear unit PU in the axialdirection. Further, the friction disk 176 is arranged in a position atwhich it overlaps the planetary gear PR at an outer diameter side in adiametrical direction.

[0182] The oil chamber 166 a communicates with an oil passage 193 of theboss portion 3 d ₃, and the oil passage 193 communicates with thehydraulic control apparatus (not shown). In other words, in thehydraulic servo 166, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 166 a is configured from a pair ofsealing rings 182 sealing a portion between the boss portion 3 d ₃ ofthe case 3 and the drum-like member 132 having the cylinder portion 166e.

[0183] The friction disk 176 is spline engaged to an inner peripheralside of the clutch drum 132 of the clutch C3, and an inner peripheralside of the friction disk 176 is spline engaged to the ring gear R1.That is, the clutch drum 132 and the ring gear R1 can be selectivelyengaged by the clutch C3. Further, the brake (the second brake) B2having the hydraulic servo 164 and the friction disk 174 is arranged atan outer peripheral side of the clutch drum 132, an outer peripheralside of the friction disk 174 is spline engaged to the spline 3 s formedin the inner periphery of the transmission case 3 b, and an innerperipheral side of the friction disk 174 is spline engaged to an outerperipheral side of a leading end portion of the clutch drum 132, thatis, the clutch drum 132 can be selectively engaged by the brake B2.

[0184] The carrier CR1 which has a side plate 133 ₃, a side plate 134 ₃,and the pinions P1 a, P1 b (refer to FIG. 12) supported by the sideplates 133 ₃, 134 ₃, meshes with the ring gear R1 via the pinion P1 a.The side plate 134 ₃ is firmly fixed to the center shaft 30 ₃ describedabove (the input rotation is always input). Further, the carrier CR1meshes with the sun gear S1 which is spline engaged to the boss portion3 d ₃ of the case 3 as described above so as to be incapable of rotating(be always fixed), via the pinion P1 b. In this case, the ring gear R1is rotatably supported on the center shaft 30 ₃ by a disc-shaped member135 ₃.

[0185] Further, a transmission member (a reduced rotation output unit)140 ₃, which is rotatably supported on the center shaft 30 ₃ via thesleeve member 126 ₃ and the side plate 142 ₃ of the carrier CR3 andwhich transmits the rotation of the clutch drum 132, is connected to aninner peripheral side of a leading end portion of the clutch drum 132.The ring gear R3 of the second simple planetary SP3 in the planetarygear unit PU is firmly fixed to approximately an intermediate portion ofthe transmission member 140 ₃.

[0186] The one-way clutch (the second one-way clutch) F2 is positionedat the outer peripheral side of the ring gear R3, and the inner race 141of the one-way clutch F2 is spline engaged to the outer peripheral sideof the ring gear R3. Further, the brake (the fourth brake) B3, havingthe hydraulic servo 167 and the friction disk 177, is positioned at theouter peripheral side of the outer race 148 in the one-way clutch F2,the inner peripheral side of the friction disk 177, is spline engaged tothe outer race 148, and the outer peripheral side of the friction disk177 is spline engaged to the spline 3 s formed in the inner periphery ofthe transmission case 3 b, that is, the outer race 148 that can beselectively engaged by the brake B3.

[0187] Further, the carrier CR3, which has the side plate 142 ₃, that isspline engaged to the sleeve member 126 ₃ as described above, the sideplate 143, and the pinion P3 supported in the side plates 142 ₃, 143,meshes with the inner peripheral side of the ring gear R3 via the pinionP3, and the carrier CR3 meshes with the sun gear S3 formed in the sleevemember 127 via the pinion P3. The side plate 143 of the carrier CR3 isspline engaged to the ring gear R2 of the first simple planetary SP2 ofthe planetary gear unit PU.

[0188] The ring gear R2 is configured such that the ring gear R2 itselfforms the inner race of the one-way clutch F3, the one-way clutch (thefirst one-way clutch) F3 is arranged at the outer peripheral side of oneend of the ring gear R2, and the outer race of the one-way clutch F3 isspline engaged to the spline 3 s formed in the inner periphery of thetransmission case 3 b. Further, the brake (the third brake) B4, havingthe hydraulic servo 163 and the friction disk 173, is arranged at theouter peripheral side of the other end of the ring gear R2, the innerperipheral side of the friction disk 173 is spline engaged to the hubmember 147 firmly fixed to the ring gear R2, and the outer peripheralside of the friction disk 173 is spline engaged to the spline 3 s formedin the inner periphery of the transmission case 3 b, that is, the ringgear R2 that can be selectively engaged by the brake B4.

[0189] Further, the carrier CR2 having the side plate 144, the sideplate 145, and the pinion P2, supported by the side plates 144, 145,meshes with the inner peripheral side of the ring gear R2 via the pinionP2, and the carrier CR2 meshes with the sun gear S2 formed in the sleevemember 127 via the pinion P2. Further, the carrier CR2 is connected tothe counter gear 50 via the side plate 145.

[0190] In the same manner, for example, as in the automatictransmissions 1 ₁, 1 ₂, shown in FIG. 1 or 6, the gear 51 that is fixedonto the fourth counter shaft 52 of the counter shaft portion 4 mesheswith the counter gear 50, and the gear 53 of the differential portion 5meshes with the counter shaft 52 via the gear 52 a formed on an outerperipheral surface. Further, the gear 53 is fixed to the housing 54, andthe housing 54 is connected to the right and left axles (not shown) viathe differential gear 55.

[0191] As described above, the clutch C1 and the clutch C2 are arrangedon the input shaft 20, and the counter gear 50, the planetary gear unitPU and the planetary gear PR are arranged on the center shaft 30 ₃ inthat order. In other words, the planetary gear PR is arranged at oneside of the planetary gear unit PU in the axial direction, the clutch C1and the clutch C2 are arranged at the other side in the axial direction,and the counter gear 50 is arranged between the clutch C1, the clutch C2and the planetary gear unit PU. Further, the clutch C3 and the brake B2are arranged at the outer peripheral side of the planetary gear PR, andthe brake B3 and the brake B4 are arranged at the outer peripheral sideof the planetary gear unit PU, respectively. Further, the planetary gearPR, the planetary gear unit PU and the counter gear 50 are providedcoaxially with the input shaft 20.

[0192] Next, a description will be given of an operation of theautomatic transmission 1 ₃ with reference to FIGS. 12, 13 and 14 on thebasis of the structure described above. It should be noted that, in thevelocity diagram shown in FIG. 14, the vertical axis indicates arotation speed of each of the rotation elements, and the horizontal axisindicates and corresponds to a gear ratio of each of the rotationelements. Further, in the portion for the planetary gear unit PU in thevelocity diagram, the vertical axis of the endmost portion in thehorizontal direction (the right side in FIG. 14) corresponds to the ringgear R3, and from there toward the left side of the drawing, thevertical axes corresponds to the ring gear R2 and the carrier CR3, thecarrier CR2, and the sun gears S2, S3, in that order.

[0193] As shown in FIG. 12, the rotation of the input shaft 20 is inputto the sun gear S2 and the sun gear S3 with the engagement of the clutchC1. The rotation of the input shaft 20 is input to the carrier CR3 andthe ring gear R2 with engagement of the clutch C2; and the carrier CR2and the ring gear R2 can have their rotation selectively fixed inaccordance with engagement of the brake B4, and restricted to onedirection by the one-way clutch F3.

[0194] On the other hand, the rotation of the input shaft 20 is input tothe carrier CR1 via the center shaft 30 ₃, the sun gear S1 is fixed inrotation with respect to the case 3, and the ring gear R1 is rotated ata reduced speed as a result of the rotation of the input shaft 20 inputto the carrier CR1. The reduced rotation of the ring gear R1 is input tothe ring gear R3 via the transmission member 140 ₃ with the engagementof the clutch C3. Further, the ring gear R3 is controlled so as torotate in one direction by the one-way clutch F3 that operates withengagement of the brake B3, and can have its rotation selectively fixedwith the engagement of brake B2. Further, the rotation of the ring gearR2 is output to the counter gear 50, and is output to the driven wheel(not shown) via the counter gear 50, the counter shaft portion 4 and thedifferential portion 5 (refer to FIG. 1 or 6).

[0195] In the forward first speed in the drive (D) range, as shown inFIG. 13, the clutch C1 and the one-way clutch F3 are engaged.Accordingly, as shown in FIG. 14, the rotation of the input shaft 20 isinput to the sun gears S2, S3 via the clutch C1, and the rotation of thecarrier CR3 and the ring gear R2 is restricted to one direction (aforward rotation direction), that is, the ring gear R2 is prevented fromrotating backward, and is thereby placed in a fixed state. Further, thereduced rotation is output to the carrier CR2 by the rotation of theinput shaft 20 input to the sun gear S2 and the fixed ring gear R2, anda forward rotation that corresponds to the forward first speed is outputfrom the counter gear 50. In this case, in the planetary gear PR, thereduced rotation is output to the ring gear R1 by the carrier CR1 towhich the rotation of the input shaft 20 is input and the fixed sun gearS1. However, because the clutch C3 is disengaged, the torque is nottransmitted to the transmission member 140 ₃. Further, when enginebraking (coasting) takes place, the forward first speed state ismaintained such that the brake B4 is engaged so as to fix the ring gearR2, and prevent the ring gear R2 from rotating forward.

[0196] In this case, in the forward first speed, because the one-wayclutch F3 prevents the ring gear R2 from rotating backward and allows itto rotate forward, it is possible to smoothly achieve the forward firstspeed by automatic engagement of the one-way clutch F3, for example, ata time of changing from a non-running range to a running range.

[0197] In the forward second speed in the drive (D) range, as shown inFIG. 13, the clutch C1 and the one-way clutch F2 are engaged.Accordingly, as shown in FIG. 14, the rotation of the input shaft 20 isinput to the sun gears S2, S3 via the clutch C1, and the rotation of thering gear R3 is restricted to one direction (the forward rotationdirection), that is, the ring gear R3 is prevented from rotating inreverse and is in a fixed state. Thus, the reduced rotation is output tothe carrier CR3 and the ring gear R2 by the rotation of the input shaft20 input to the sun gear S3 and the fixed ring gear R3; accordingly, alarger reduced rotation than that of the forward first speed describedabove is output to the carrier CR2 by the rotation of the input shaft 20input to the sun gear S2 and the reduced rotation input to the ring gearR2, and a forward rotation that corresponds to the forward second speedis output from the counter gear 50. In this case, at this time, in theplanetary gear PR, the reduced rotation is output to the ring gear R1 bythe carrier CR1 to which the rotation of the input shaft 20 is input andthe fixed sun gear S1. However, the clutch C3 is disengaged, so thetorque is not transmitted to the transmission member 140 ₃. Further,when engine brake (coasting) takes place, the forward second speed stateis maintained such that the brake B2 is engaged so as to fix the ringgear R3, and prevent the ring gear R3 from forward rotating.

[0198] In this case, when shifting from the forward first speed to theforward second speed, the brake B3 is engaged and the one-way clutch F2prevents the ring gear R3 from rotating in reverse, whereby the carrierCR3 and the ring gear R2 rotate forward and are automaticallydisconnected by the one-way clutch F3 engaged in the forward firstspeed. Accordingly, the shift to the forward second speed can besmoothly executed, for example, while preventing the engine from racing.

[0199] In the forward third speed in the drive (D) range, as shown inFIG. 13, the clutch C1 and the clutch C3 are engaged. Accordingly, asshown in FIG. 14, the rotation of the input shaft 20 is input to thecarrier CR1, and the ring gear R1 is rotated at reduced speed by thefixed sun gear S1. Further, the reduced rotation of the ring gear R1 isinput to the ring gear R3 via the transmission member 140 ₃. On theother hand, the rotation of the input shaft 20 is input to the sun gearS3, a slightly larger reduced rotation is output to the carrier CR3 andthe ring gear R2 in accordance with the rotation of the input shaft 20input to the sun gear S3 and the reduced rotation of the ring gear R3, alager reduced rotation than that of the forward second speed describedabove is output to the carrier CR2 in accordance with the rotation ofthe input shaft 20 input to the sun gear S2 and the slightly largerreduced rotation input to the ring gear R2. Thus, and the forwardrotation that corresponds to the forward third speed is output from thecounter gear 50. In this case, at this time, because the ring gear R1and the ring gear R3 rotate at the reduced speed, the transmissionmember 140 ₃ transmits a comparatively large torque.

[0200] In the forward fourth speed in the drive (D) range, as shown inFIG. 13, the clutch C1 and the clutch C2 are engaged. Accordingly, asshown in FIG. 14, the rotation of the input shaft 20 is input to the sungears S2, S3 via the clutch C1 and to the carrier CR3 and the ring gearR2 via the clutch C2. Thus, the rotation of the input shaft 20 is outputas it is to the carrier CR2 in accordance with the rotation of the inputshaft 20 input to the sun gear S2 and the rotation of the input shaft 20input to the ring gear R2, that is, in a directly connected state, and aforward rotation that corresponds to the forward fourth speed is outputfrom the counter gear 50. In this case, at this time, in the planetarygear PR, the reduced rotation is output to the ring gear R1 by thecarrier CR1 to which the rotation of the input shaft 20 is input and thefixed sun gear S1. However, because the clutch C3 is disconnected, thetorque is not transmitted to the transmission member 140 ₃.

[0201] In the forward fifth speed in the drive (D) range, as shown inFIG. 13, the clutch C2 and the clutch C3 are engaged. Accordingly, asshown in FIG. 14, the rotation of the input shaft 20 is input to thecarrier CR1, and the ring gear R1 is rotated at a reduced speed by thefixed sun gear S1. Further, the reduced rotation of the ring gear R1 isinput to the ring gear R3 via the transmission member 140 ₃ inaccordance with the engagement of the clutch C3. On the other hand, therotation of the input shaft 20 is input to the carrier CR3 and the ringgear R2; an increased rotation is output to the sun gears S2, S3 inaccordance with the rotation of the input shaft 20 input to the carrierCR3 and the reduced rotation of the ring gear R3; an increased rotationis output to the carrier CR2 in accordance with the rotation of theinput shaft 20 input to the ring gear R2 and the increased rotationinput to the sun gear S2, and a forward rotation that corresponds to theforward fifth speed is output from the counter gear 50. In this case, atthis time, in the same manner as the forward third speed state describedabove, because the ring gear R1 and the ring gear R3 rotate at thereduced speed, the transmission member 140 ₃ transmits a comparativelylarge torque.

[0202] In the forward sixth speed in the drive (D) range, as shown inFIG. 13, the clutch C2 and the brake B2 are engaged. Accordingly, asshown in FIG. 14, the rotation of the input shaft 20 is input to thecarrier CR3 and the ring gear R2 via the clutch C2, and the ring gear R3is fixed in accordance with the engagement of the brake B2. Thus, therotation becomes an increased rotation (larger than the forward fifthspeed described above) in accordance with the rotation of the inputshaft 20 input to the carrier CR3 and the fixed ring gear R3, and theincreased rotation is output to the sun gears S3, S2, and a greaterincreased rotation than the forward fifth speed is output to the carrierCR2 in accordance with the rotation of the input shaft 20 input to thering gear R2 and the increased rotation input to the sun gear S2.Accordingly, a forward rotation that corresponds to the forward sixthspeed is output from the counter gear 50. In this case, at this time, inthe planetary gear PR, the reduced rotation is output to the ring gearR1 by the carrier CR1 to which the rotation of the input shaft 20 isinput and the fixed sun gear S1. However, because the clutch C3 isdisengaged, the torque is not transmitted to the transmission member 140₃.

[0203] In the backward first speed in the reverse (R) range, as shown inFIG. 13, the clutch C3 and the brake B4 are engaged. Accordingly, asshown in FIG. 14, the rotation of the input shaft 20 is input to thecarrier CR1, and the ring gear R1 rotates at a reduced speed due to thefixed sun gear S1. Further, the reduced rotation of the ring gear R1 isinput to the ring gear R3 via the transmission member 140 ₃ inaccordance with the engagement of the clutch C3. On the other hand, therotation of the carrier CR3 and the ring gear R2 is fixed in accordancewith the engagement of the brake B4. Accordingly, a reverse rotation isoutput to the sun gears S2, S3 by the fixed carrier CR3 and the reducedrotation of the ring gear R3, the reverse rotation is output to thecarrier CR2 by the fixed ring gear R2 and the reverse rotation input tothe sun gear S2, and a reverse rotation that corresponds to the backwardfirst speed is output from the counter gear 50. In this case, at thistime, because the ring gear R1 and the ring gear R3 rotate at thereduced speed in the same state as in the forward third speed and theforward fifth speed, the transmission member 140 ₃ transmits acomparatively large torque.

[0204] In the parking (P) range and the neutral (N) range, inparticular, the clutch C1, the clutch C2 and the clutch C3 aredisengaged, and power transmission between the input shaft 20 and thecounter gear 50 is in an interrupted state, so that the entire automatictransmission 1 ₃ is in a slipping state (a neutral state).

[0205] As described above, in the automatic transmission 1 ₃ accordingto the invention, the planetary gear PR, the clutch C3 and thetransmission member 140 ₃ which correspond to the reduced rotationoutput unit are arranged at one side (the left side in FIGS. 11 and 12)in the axial direction of the planetary gear unit PU, the clutch C1 andthe clutch C2 are arranged at the other side (the right side in FIGS. 11and 12) in the axial direction of the planetary gear unit PU, and thecounter gear 50 that corresponds to the output member is arrangedbetween the clutch C1, the clutch C2 and the planetary gear unit PU. Asa result, it is possible to arrange, in particular, the planetary gearPR and the planetary gear unit PU at positions that are close to eachother, and it is possible to make the axial direction length of thetransmission member 140 ₃, that transmits the reduced rotation,comparatively short. Therefore, it is possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₃, and it ispossible to make the inertia (the inertia force) small in accordancewith the weight saving of the transmission member 140 ₃. Accordingly, itis possible to improve the controllability of the automatic transmission1 ₃, and it is possible to reduce the generation of shift shock.

[0206] Further, because the clutch C1 is connected to the sun gear S2and the sun gear S3 via the outer peripheral side of the clutch C2, itis possible to prevent the member that connects each of the rotationelements from being complicated, and it is possible to make theautomatic transmission 1 ₃ compact.

[0207] Further, the clutch C2 is structured such that the clutch C1 isarranged at the outer peripheral side thereof, and thus can not have itsdiameter enlarged to the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 162 and, more particularly, thepressure receiving area of the oil chamber 162 a for the hydraulic servo162, is large at the inner peripheral side by providing the hydraulicservo 162 on the input shaft 20 (in comparison with the case, forexample, that the hydraulic servo 162 is provided on the boss portion 3c), and it is possible to increase the capacity of the clutch C1.

[0208] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case that the automatic transmission 1 ₃ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and it is possible to improve ease of vehiclemounting of the automatic transmission 1 ₃.

[0209] Further, the clutch C3 connects and disconnects the output of thereduced rotation. Accordingly, by disengaging the clutch C3, it ispossible to make the rotation of the input shaft that is input to thecarrier CR1 rotate idly using the planetary gear PR and, moreparticularly, using the ring gear R1, while at the same time it ispossible to selectively output the reduced rotation to the ring gear R3.As a result, it is possible to directly fix the sun gear S1 to the case3, or the like, without providing a brake, and it is possible to achievea compact structure and weight saving of the automatic transmission 1 ₃.Further, because a brake fixing the sun gear S1 is not provided, it ispossible to dispose the brake B2 that selectively engages the ring gearR3 at the outer peripheral side of the planetary gear PR.

[0210] Additionally, because the hydraulic servo 162 is provided on theinput shaft 20, it is possible to supply oil to the oil chamber 162 a ofthe hydraulic servo 162 by preventing the oil from leaking from the case3 using a pair of sealing rings 181, and supplying the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 162. Further, the hydraulic servos 161, 166 can supplythe oil from the boss portions 3 c, 3 d ₃ that respectively extend fromthe case 3, for example, without passing through other members, that is,the oil can be supplied by respectively arranging a pair of sealingrings 180, 182. Accordingly, it is possible to supply the oil to thehydraulic servos 162, 161, 166 by simply providing the respective pairsof sealing rings 181, 180, 182, and it is possible to minimize thesliding resistance resulting from the sealing rings, whereby it ispossible to improve the efficiency of the automatic transmission 1 ₃.

[0211] Further, because the friction disk 176 is arranged at an outerperipheral side of the planetary gear PR in the diametrical direction,it is possible to make the automatic transmission 1 ₃ compact in theaxial direction. Also, because it is possible to arrange the planetarygear PR and the planetary gear unit PU adjacent to each other byarranging the planetary gear PR between the hydraulic servo 166 of theclutch C3 and the planetary gear unit PU in the axial direction (as thehydraulic servo 166 of the clutch C3 is not provided between theplanetary gear PR and the planetary gear unit PU), it is possible tomake the transmission member 140 ₃ comparatively short. Accordingly, itis possible to achieve a compact structure and weight saving for theautomatic transmission 1 ₃. It is also possible to make the inertia (theinertia force) small, to improve the controllability of the automatictransmission 1 ₃, and to reduce the generation of shift shock.

[0212] Further, as the planetary gear PR is a double pinion planetarygear, it is possible to output the rotation of the input shaft 20 as thereduced rotation. Further, even in the case that the gear ratio of theautomatic transmission 1 ₃ is set favorably, high speed rotation can berestricted without making each of the rotation elements of the planetarygear unit and the speed reduction planetary gear large. Accordingly, itis possible to make the automatic transmission 1 ₃ compact.

[0213] Further, because the planetary gear unit PR is configured suchthat it includes the carrier CR1 that corresponds to the input rotationelement, the sun gear S1 that corresponds to the fixed element, and thering gear R1 that corresponds to the output rotation element, it ispossible to output the rotation of the input shaft 20 as the reducedrotation.

[0214] In addition, as the planetary gear unit PU is configured from thefirst simple planetary gear SP2 having the sun gear S2, the carrier CR2and the ring gear R2, and the second simple planetary gear SP3 havingthe sun gear S3, the carrier CR3 and the ring gear R3, it is possible toposition the planetary gear PR and the planetary gear unit PU close toeach other while, at the same time, it is possible to achieve, forexample, the six forward speeds and the one backward speed. Accordingly,it is possible to make the transmission member 140 ₃, that transmits thereduced rotation, comparatively short.

[0215] Further, the one-way clutch F3 is provided in parallel to thebrake B4 and restricts the rotation of the carrier CR3 and the ring gearR2 to one direction. Thus, it is possible to achieve, for example, theforward first speed at a time of normal running in accordance with theengagement of the clutch C1 and the one-way clutch F3. As a result, itis possible to smoothly achieve the forward first speed, for example, ata time of changing from a non-running range to a running range.

[0216] Further, as the brake B4 and the one-way clutch F3 are arrangedat the outer peripheral side of the planetary gear unit PU, it ispossible to make the portion in which the clutches C1, C2 are arrangedcompact in the axial direction in comparison with the case, for example,where the one-way clutch F3 is positioned adjacent to the clutch C2(particularly for restricting the rotation of the hub member 123 in onedirection). As a result, it is possible to position the counter gear 50closer to the torque converter side. Further, it is possible to positionthe gear 51 of the counter shaft 52 closer to the torque converter side,and it is possible to make the counter shaft portion 4 compact in theaxial direction.

[0217] In addition, because the inner race of the one-way clutch F3 andthe ring gear R2 are integrally formed, it is possible to make theautomatic speed change mechanism 2 ₃ of the automatic transmission 1 ₃compact in the diametrical direction, while, at the same time, ispossible to make the counter shaft portion 4 compact in the axialdirection.

[0218] Further, the one-way clutch F2 is provided which is positioned inparallel to the brake B2 and which restricts the rotation of the ringgear R3 to one direction in accordance with the braking of the brake B3.Thus, it is possible to smoothly carry out shifting, for example, fromthe forward second speed to the forward third speed.

[0219] Additionally, as shown in the velocity diagram, it is possible toarrange the planetary gear PR and the planetary gear unit PU close toeach other while achieving the six forward speeds and the one backwardspeed, and it is possible to make the transmission member 140 ₃, thattransmits the reduced rotation, short. Accordingly, it is possible toachieve a compact structure and weight saving in the automatictransmission 1 ₃, and it is possible to make the inertia (the inertiaforce) small. As a result, it is possible to improve the controllabilityof the automatic transmission 1 ₃ and to reduce the generation of shiftshock.

[0220] Further, the configuration allows the six forward speeds and theone backward speed to be achieved. Both the clutches C1, C2 are engagedin the forward fourth speed, that is, the directly connected state isestablished in the forward fourth speed. As a result, it is possible toset the gear ratio in the forward fifth speed and the forward sixthspeed so that it is high. In the case, in particular, of a vehiclerunning at a high speed for which mounting has been executed, it ispossible to make the engine speed low, and it is possible to contributeto quietness of the vehicle when running at high speed.

[0221] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4; accordingly, it is possible to mount theautomatic transmission 1 ₃, for example, in the FF vehicle.

[0222] Hereinafter, a description will be given, with reference to FIGS.15 to 18, of a fourth embodiment that is a partial modification of thethird embodiment. It should be noted that, in the fourth embodiment,with the exception of partially modified portions, the same referencenumerals denote the same portions as those of the third embodiment, anda description thereof will be omitted.

[0223] As shown in FIGS. 15 and 16, an automatic transmission 1 ₄according to the fourth embodiment, as compared with the automatictransmission 1 ₃ according to the third embodiment (refer to FIGS. 11and 12), is structured such that the rotation of the input shaft 20 isinput to the sun gear (the input rotation element, the first sun gear)S1 instead of the carrier CR1 of the planetary gear (the reducedrotation output unit, the speed reduction planetary gear) PR.

[0224] As shown in FIG. 15, in an automatic speed change mechanism 2 ₄,the sun gear S1 is integrally formed with an intermediate shaft 30 ₄ atan outer peripheral side (the left side in FIG. 15) of one end of theintermediate shaft 30 ₄ at the opposite side to the input shaft 20, andthe input rotation is always input. Further, on a boss portion 3 d ₄,that is provided with a fixed sleeve-like member 131 ₄, a side plate 133₄ of the carrier (the fixed element, the first carrier) CR1 is splineengaged to the sleeve-like member 131 ₄ so as to be firmly fixed (alwaysfixed) onto the boss portion 3 d ₄. The carrier CR1 has the pinions P1a, P1 b (refer to FIG. 16) that are supported by the other side plate134 ₄; the pinion P1 b meshes with the sun gear S1, and the pinion P1 ameshes with the ring gear (the output rotation element, the first ringgear) R1. The ring gear R1 is rotatably supported in the sleeve-likemember 131 ₄ by a disc-shaped member 135 ₄.

[0225] On the other hand, a transmission member (the reduced rotationoutput unit) 140 ₄, which is rotatably supported on the center shaft 30₄ and which transmits the rotation of the clutch drum 132, is connectedto an inner peripheral side of a leading end portion of the clutch drum(the third clutch drum) 132. Further, the ring gear R3 of the secondsimple planet SP3 in the planetary gear unit PU is firmly fixed to asubstantially central portion of the transmission member 140 ₄. Further,the side plate 142 ₄ of the carrier CR3 in the second simple planet SP3is integrally formed with a sleeve member 126 ₄ which is spline engagedto the hub member 123 of the clutch C2. In this case, the clutch drum132 is open in the direction of the planetary gear PR, and the planetarygear PR is arranged between the hydraulic servo 166 and the planetarygear unit PU in the axial direction. Further, the friction disk 176 ispositioned so as to overlap with the outer diameter side of theplanetary gear PR in the diametrical direction.

[0226] Next, a description will be given of an operation of theplanetary gear PR of the automatic transmission 1 ₄ with reference toFIGS. 16, 17 and 18 on the basis of the structure described above. Inthis case, in the same manner as the third embodiment described above,in the velocity diagram shown in FIG. 18, the vertical axis indicatesthe rotation speed of each of the rotation elements, and the horizontalaxis indicates and corresponds to a gear ratio of each of the rotationelements. Further, in a portion for the planetary gear unit PU in thevelocity diagram, the vertical axis of the endmost portion in thehorizontal direction (the right side in FIG. 18) corresponds to the ringgear R3, and from there toward the left side of the drawing, thevertical axes correspond to the ring gear R2 and the carrier CR3, thecarrier CR2, the sun gears S2, S3, in that order.

[0227] As shown in FIG. 16, the rotation of the input shaft 20 is inputto the sun gear S1 via the intermediate shaft 30 ₄, the carrier CR1 isfixed in rotation with respect to the case 3, and the ring gear R1rotates at a reduced speed as a result of the rotation of the inputshaft 20 input to the sun gear S1. The reduced rotation of the ring gearR1 is input to the ring gear R3 via the transmission member 140 ₄ inaccordance with the engagement of the clutch C3.

[0228] Accordingly, as shown in FIGS. 17 and 18, in the forward firstspeed, the forward second speed, the forward fourth speed and theforward sixth speed, in the planetary gear PR, the reduced rotation isoutput to the ring gear R3 by the sun gear S1 to which the rotation ofthe input shaft 20 is input and the fixed carrier CR1. However, becausethe clutch C3 is disengaged, the torque is not transmitted to thetransmission member 140 ₄. On the other hand, in the forward thirdspeed, the forward fifth speed and the backward first speed, in theplanetary gear PR, because the clutch C3 is engaged, the ring gear R3rotates at a reduced speed due to the sun gear S1 to which the rotationof the input shaft 20 is input and the fixed carrier CR1, and thereduced rotation of the ring gear R1 is output to the ring gear R3 viathe clutch C3 and the transmission member 140 ₄. At this time, as thering gear R1 and the ring gear R3 rotate at the reduced speed, thetransmission member 140 ₄ transmits a comparatively large torque.

[0229] It should be noted that because the operations other than that ofthe planetary gear PR are the same as those of the third embodimentdescribed above, a description thereof will be omitted.

[0230] As described above, with the automatic transmission 1 ₄ accordingto the invention, the planetary gear PR, the clutch C3 and thetransmission member 140 ₄ which correspond to the reduced rotationoutput unit are arranged at one side (the left side in FIGS. 15 and 16)in the axial direction of the planetary gear unit PU; the clutch C1 andthe clutch C2 are arranged at the other side (the right side in FIGS. 15and 16) in the axial direction of the planetary gear unit PU, and thecounter gear 50 that corresponds to the output member is arrangedbetween the clutch C1, the clutch C2 and the planetary gear unit PU. Asa result, it is possible, in particular, to position the planetary gearPR and the planetary gear unit PU close to each other, and it ispossible to make the length of the transmission member 140 ₄ thattransmits the reduced rotation comparatively short in the axialdirection. Accordingly, because it is possible to achieve a compactstructure and weight saving in the automatic transmission 1 ₄, and it ispossible to make the inertia (the inertia force) small in accordancewith the weight saving of the transmission member 140 ₄, it is possibleto improve the controllability of the automatic transmission 1 ₄ and toreduce the generation of shift shock.

[0231] Further, because the clutch C1 is connected to the sun gears S2,S3 via the outer peripheral side of the clutch C2, it is possible toprevent the member that connects each of the rotation elements frombeing complicated, and it is possible to make the automatic transmission1 ₄ compact.

[0232] Further, the clutch C2 is structured such that the clutch C1 isarranged at the outer peripheral side thereof, and can not have itsdiameter enlarged to the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 162, and more particularly, thepressure receiving area of the oil chamber 162 a for the hydraulic servo162, is large at the inner peripheral side by providing the hydraulicservo 162 on the input shaft 20 (in comparison with the case, forexample, that the hydraulic servo 162 is provided on the boss portion 3c), and it is possible to increase the capacity of the clutch C1.

[0233] Further, since the planetary gear PR, the planetary gear unit PUand the counter gear 50 are provided coaxially with the input shaft 20,it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case that the automatic transmission 1 ₄ is mountedin the FF vehicle, (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with, for example, by avehicle body member, and it is possible to improve the ease of mountingof the automatic transmission 1 ₄.

[0234] Further, the clutch C3 connects and disconnects the output of thereduced rotation. Accordingly, by disengaging the clutch C3, it ispossible to make the rotation of the input shaft that is input to thesun gear S1 rotate idly using the planetary gear PR and, moreparticularly, using the ring gear R1, while, at the same time, it ispossible to selectively output the reduced rotation to the ring gear R3.As a result, it is possible to directly fix the sun gear S1 to the case3, or the like, without providing a brake, and it is possible to achievea compact structure and weight saving for the automatic transmission 1₃. Further, because a brake for fixing the carrier CR1 is not provided,it is possible to dispose the brake B2 that selectively engages the ringgear R3 at the outer peripheral side of the planetary gear PR.

[0235] Further, as the hydraulic servo 162 is provided on the inputshaft 20, it is possible to supply oil to the oil chamber 162 a of thehydraulic servo 162 by preventing the oil from leaking from the case 3using a pair of sealing rings 181, and supplying the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 162. Further, the hydraulic servos 161, 166 can supplythe oil from the boss portions 3 c, 3 d that extend from the case 3, forexample, without passing the oil through other members, that is, the oilcan be supplied by respectively providing the pairs of sealing rings180, 182. Accordingly, it is possible to supply the oil to the hydraulicservos 162, 161, 166 by simply providing the respective pairs of sealingrings 181, 180, 182 and to minimize the sliding resistance resultingfrom the sealing rings. As a result, it is possible to improve theefficiency of the automatic transmission 1 ₄.

[0236] Further, because the friction disk 176 is positioned at an outerperipheral side of the planetary gear PR in the diametrical direction,it is possible to make the automatic transmission 1 ₄ compact in theaxial direction. Additionally, as it is possible to position theplanetary gear PR and the planetary gear unit PU adjacent to each otherby arranging the planetary gear PR between the hydraulic servo 166 ofthe clutch C3 and the planetary gear unit PU in the axial direction(because the hydraulic servo 166 of the clutch C3 is not providedbetween the planetary gear PR and the planetary gear unit PU), it ispossible to make the transmission member 140 ₄ comparatively short.Accordingly, it is possible to achieve a compact structure and weightsaving for the automatic transmission 1 ₄ and to make the inertia (theinertia force) small. Accordingly, it is possible to improve thecontrollability of the automatic transmission 1 ₄ and to reduce thegeneration of shift shock.

[0237] Further, because the planetary gear PR is the double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case that the gearratio of the automatic transmission 1 ₄ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gearlarger. Accordingly, it is possible to make the automatic transmission 1₄ compact.

[0238] In addition, because the planetary gear unit PR is structuredsuch that the sun gear S1 corresponds to the input rotation element, thecarrier CR1 corresponds to the fixed element, and the ring gear R1corresponds to the output rotation element, it is possible to output therotation of the input shaft 20 as the reduced rotation.

[0239] Further, the planetary gear unit PU is configured from the firstsimple planetary gear SP2 having the sun gear S2, the carrier CR2 andthe ring gear R2, and the second simple planetary gear SP3 having thesun gear S3, the carrier CR3 and the ring gear R3; accordingly, theconfiguration allows realization of, for example, the six forward speedsand the one backward speed, while, at the same time, it is also possibleto position the planetary gear PR and the planetary gear unit PU closerto each other, and make the transmission member 140 ₄, that transmitsthe reduced rotation comparatively short.

[0240] Also, because the one-way clutch F3 is positioned in parallel tothe brake B4 and restricts the rotation of the carrier CR3 and the ringgear R2 to one direction, it is possible to achieve, for example, theforward first speed at a time of normal running by engagement of theclutch C1 and the one-way clutch F3. Thus, it is possible to smoothlyachieve the forward first speed, for example, at a time of changing froma non-running range to a running range.

[0241] Further, because the brake B4 and the one-way clutch F3 arearranged at the outer peripheral side of the planetary gear unit PU, itis possible to make the portion in which the clutches C1, C2 arearranged compact in the axial direction in comparison with the case, forexample, where the one-way clutch F3 is positioned adjacent to theclutch C2 (particularly for restricting the rotation of the hub member123 in one direction). As a result, it is possible to position thecounter gear 50 closer to the torque converter side. Accordingly, it ispossible to position the gear 51 of the counter shaft 52 closer to thetorque converter side, and it is possible to make the counter shaftportion 4 compact in the axial direction.

[0242] In addition, as the inner race of the one-way clutch F3 and thering gear R2 are integrally formed, it is possible to make the automaticspeed change mechanism 2 ₄ of the automatic transmission 1 ₄ compact inthe diametrical direction, while at the same time is possible to makethe counter shaft portion 4 compact in the axial direction.

[0243] Further, as the one-way clutch F2 is disposed to be parallel withthe brake B2 and restricts the rotation of the ring gear R3 to onedirection with the braking of the brake B3, it is possible to smoothlycarry out shifting, for example, from the forward second speed to theforward third speed.

[0244] Further, as shown in the velocity diagram, the configuration issuch that it is possible to arrange the planetary gear PR and theplanetary gear unit PU close to each other while achieving the sixforward speeds and the one backward speed, and it is possible to makethe transmission member 140 ₄ that transmits the reduced rotationcomparatively short. Accordingly, because it is possible to achieve acompact structure and weight saving for the automatic transmission 1 ₄,and it is possible to make the inertia (the inertia force) small, it ispossible to improve the controllability of the automatic transmission 1₄ and reduce the generation of shift shock.

[0245] Additionally, the configuration can realize the six forwardspeeds and the one backward speed, and both the clutches C1, C2 areengaged in the forward fourth speed, that is, the directly connectedstate is established in the forward fourth speed. As a result, it ispossible to set the gear ratio in the forward fifth speed and theforward sixth speed so that it is high. In the case, in particular, of avehicle running at a high speed for which mounting has been executed, itis possible to make the engine speed low and it contributes to aquietness of the vehicle when running at high speed.

[0246] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Therefore, it is possible to mount theautomatic transmission 1 ₄, for example, in the FF vehicle.

[0247] Note that, in the first to fourth embodiments, a description isgiven of embodiments in which the torque converter 12 is provided in theautomatic transmission 1 ₄. However, the invention is not limited tothis, and any structure may be employed so long as the take-offapparatus transmits torque (rotation) at the time of take-off. Further,the description is given for the case that the automatic transmission ismounted in a vehicle in which the drive source is an engine. However,the invention is not limited to this, and the automatic transmission maybe mounted in a hybrid vehicle. That is, it goes without saying that theautomatic transmission may be mounted in a vehicle having any drivesource. Further, the automatic transmission 1 ₄ is preferably employedin an FF vehicle. However, the invention is not limited to this, and theautomatic transmission may be employed for other drive system vehicles,such as an FR vehicle, a four-wheel drive vehicle, or the like.

[0248] A description will be given below, with reference to FIGS. 19 to21, of a fifth embodiment that is a partial modification of the firstand second embodiments. In this case, in the fifth embodiment, with theexception of partially modified portions, the same reference numeralsdenote the same members as those of the first and second embodiments,and a description thereof will be omitted.

[0249] First, a description will be given of an automatic speed changemechanism 2 ₅ of the automatic transmission 1 in accordance with thefifth embodiment with reference to FIG. 19. As shown in FIG. 19, theplanetary gear unit PU and the planetary gear (the reduced rotationoutput unit, the speed reduction planetary gear) PR are provided on theinput shaft 20. The planetary gear unit PU is a so-called Ravigneauxtype planetary gear having four rotation elements, namely, a sun gear (asecond rotation element, a third sun gear) S2, a carrier (a thirdrotation element, a second carrier) CR2, a ring gear (a fourth rotationelement, a second ring gear) R2 and a sun gear (a first rotationelement, a second gear) S3, in which the carrier CR2 is provided with,in an intermeshing manner, a long pinion PL supported by side plates242, 244, that meshes with the sun gear S3 and the ring gear R2, and ashort pinion PS that meshes with the sun gear S2. Further, the planetarygear PR is a so-called double pinion planetary gear having a carrier (aninput rotation element, a first carrier) CR1 that is provided with, inan intermeshing manner, a pinion P2 which meshes with a ring gear (anoutput rotation element, a first ring gear) R1 and a pinion P1 whichmeshes with a sun gear (an input rotation element, a first sun gear) S1.

[0250] A multiple disc clutch (a first clutch) C1 having a hydraulicservo 262, a friction disk 272, a drum-like member 222 forming a clutchdrum (a first clutch drum), and a hub member (a member connected to thesecond rotation element) 223 connected to the sun gear S2, is arrangedon the input shaft 20. A multiple disc clutch (a second clutch) C2having a hydraulic servo 261, a friction disk 271, a drum member 224forming a clutch drum (a second clutch drum), and a hub member (a memberconnected to the third rotation member) 225 connected to the carrierCR2, is arranged at an outer peripheral side of the first clutch C1.

[0251] The hydraulic servo 262 is configured from a piston member (afirst piston) 262 b that presses the friction disk 272, a drum-likemember 222 having a cylinder portion 262 e, an oil chamber (a firsthydraulic servo oil pressure chamber) 262 a formed between the pistonmember 262 b and the cylinder portion 262 e and sealed by sealing rings262 f, 262 g, a return spring 262 c that energizes the piston member 262b in the direction of the oil chamber 262 a, and a return plate 262 dthat receives the energy of the return spring 262 c. The oil chamber 262a communicates with the oil passages 20 a, 20 b formed in the inputshaft 20, and the oil passage 20 a extends to one end of the case 3 andcommunicates with an oil passage 291 of the boss portion 3 c provided soas to have a sleeve shape on the input shaft 20. Further, the oilpassage 291 communicates with the hydraulic control apparatus (notshown). In other words, because the hydraulic servo 262 is arranged onthe input shaft 20, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 262 a is configured by a pair of sealingrings 281 sealing a portion between the boss portion 3 c of the case 3and the input shaft 20.

[0252] Further, the hydraulic servo 261 is configured from a pistonmember (a second piston) 261 b that presses the friction disk 271, adrum-like member 224 having a cylinder member 261 e, an oil chamber (asecond hydraulic servo oil pressure chamber) 261 a formed between thepiston member 261 b and the cylinder member 261 e and sealed by sealingrings 261 f, 261 g, a return spring 261 c that energizes the pistonmember 261 b in the direction of the oil chamber 261 a, and a returnplate 261 d that receives the energy of the return spring 261 c. The oilchamber 261 a communicates with an oil passage 292 of the boss portion 3c, and the oil passage 292 communicates with the hydraulic controlapparatus (not shown). In other words, in the hydraulic servo 261, anoil passage from the hydraulic control apparatus (not shown) to the oilchamber 261 a is configured from a pair of sealing rings 280 that seal aportion between the boss portion 3 c of the case 3 and the cylindermember 261 e.

[0253] In other words, the drum-like member 222 described above isconnected to the input shaft 20, and the clutch C1, that can beselectively engaged by the hydraulic servo 262 for the clutch C1, ispositioned and spline engaged at an inner peripheral side of a leadingend portion of the drum-like member 222. An inner peripheral side of theclutch C1 is connected by spline engagement to the hub member 223 andthe hub member 223 is connected to the sun gear S2. Further, the clutchC2, that can be selectively engaged by the hydraulic servo 261 for theclutch C2, is positioned and spline engaged at an inner peripheral sideof a leading end portion of the drum-like member 224. The hub member 225is connected by spline engagement to the inner peripheral side of theclutch C2 and is further connected to the carrier CR2.

[0254] On the other hand, a multiple disc clutch C3, having a hydraulicservo 265, a friction disk 275, a drum-like member 232 forming a clutchdrum (a third clutch drum), and a hub member 235 connected to the ringgear R1, is arranged on the other end (the left side in the drawing) ofthe input shaft 20. The hydraulic servo 265 is configured from a pistonmember 265 b that presses the friction disk 275, a drum-like member 232having a cylinder portion 265 e, an oil chamber 265 a formed between thepiston member 265 b and the cylinder portion 265 e and sealed by sealingrings 265 f, 265 g, a return spring 265 c that energizes the pistonmember 265 b in the direction of the oil chamber 265 a, and a returnplate 265 d that receives the energy of the return spring 265 c. Notethat the clutch drum, configured from the drum-like member 232, is openin the direction of the planetary gear PR, and the planetary gear PR isarranged between the hydraulic servo 265 and the planetary gear unit PUin an axial direction. Further, the friction disk 275 is positioned suchthat it overlaps with the planetary gear PR at an outer diameter side ina diametrical direction.

[0255] The oil chamber 265 a extends to the other end of the case 3 atthe opposite side to the boss portion 3 c, and communicates with an oilpassage 293 of the boss portion 3 d provided so as to have a sleeveshape on the input shaft 20, and the oil passage 293 communicates withthe hydraulic control apparatus (not shown). In other words, in thehydraulic servo 265, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 265 a is configured by a pair of sealingrings 282 that seal a portion between the boss portion 3 d of the case 3and the drum-like member 232 having the cylinder portion 265 e.

[0256] Further, a multiple disc brake B1 having a hydraulic servo 264and a friction disk 274 is arranged at the outer peripheral side of theclutch C3 and an inner peripheral side of the case 3 b. The hydraulicservo 264 is configured from a piston member 264 b that presses thefriction disk 274, a cylinder portion 264 e formed in a part of the case3 b, an oil chamber 264 a formed between the piston member 264 b and thecylinder portion 264 e and sealed by sealing rings 264 f, 264 g, areturn spring 264 c that energizes the piston member 264 b in thedirection of the oil chamber 264 a, and a return plate 264 d thatreceives the energy of the return spring 264 c.

[0257] In other words, the drum-like 232 is rotatably supported on theboss portion 3 d, at the left side in the drawing, and the clutch (thethird clutch) C3, that can be selectively engaged by the hydraulic servo265 for the clutch C3, is positioned so as to be spline engaged at aninner peripheral side of a leading end portion of the drum-like member232. The hub member 235 in which the ring gear R1 is formed is arrangedso as to be spline engaged at the inner peripheral side of the clutchC3, and the hub member 235 is rotatably supported by the input shaft 20.Further, the brake (the second brake) B1, that can be selectivelyengaged by the hydraulic servo 264 for the brake B1, is arranged so asto be spline engaged at an outer peripheral side of the leading endportion of the drum-like member 232. Further, the carrier CR1 has thepinion P1 and the pinion P2. The pinion P2 meshes with the ring gear R1,and the pinion P1 meshes with the sun gear S1 connected to the inputshaft 20. The carrier CR1 is fixed to the boss portion 3 d of the case 3b via the side plate 231.

[0258] Further, the drum-like member 232 with which the clutch C3 andthe brake B1 are spline engaged is rotatably supported on the bossportion 3 d. The transmission member 240, that transmits the rotation ofthe ring gear R1, is connected when the clutch C3 is engaged, and thesun gear S3 of the planetary gear unit PU is connected to the other sideof the transmission member 240.

[0259] On the other hand, a multiple disc brake (a third brake) B2having a hydraulic servo 263, a friction disk 273 and a hub member 247is arranged at an outer peripheral side of the planetary gear unit PU.The hydraulic servo 263 is configured from a piston member 263 b thatpresses the friction disk 273, a cylinder portion 263 e formed in a partof the case 3 b, an oil chamber 263 a formed between the piston member263 b and the cylinder portion 263 e and sealed by sealing rings 263 f,263 g, a return spring 263 c that energizes the piston member 263 b inthe direction of the oil chamber 263 a, and a return plate 263 d thatreceives the energy of the return spring 263 c.

[0260] Further, the one-way clutch (the first one-way clutch) F3 isarranged at an outer peripheral side of the planetary gear unit PU, andan outer race of the one-way clutch F3 is spline engaged to the innerperiphery of the transmission case 3 d. A hub member 247 with which thebrake B2 is spline engaged is connected to the side plate 242 of thecarrier CR2 in the planetary gear unit PU, and an inner race of theone-way clutch F3 is connected to the hub member 247. Further, the ringgear R2 meshes with the long pinion PL of the carrier CR2, theconnection member 245 is connected to one end of the ring gear R2, andthe ring gear R2 is connected to the counter gear 50 via the connectionmember 245.

[0261] As described above, the planetary gear PR is arranged at one sideof the planetary gear unit PU in an axial direction, the clutch C1 andthe clutch C2 are arranged at the other side in the axial direction, andthe counter gear is arranged between the clutch C1, the clutch C2 andthe planetary gear unit PU. Further, the clutch C3 and the brake B1 arearranged at the outer peripheral side of the planetary gear PR, and thebrake B2 is arranged at the outer peripheral side of the planetary gearunit PU, respectively. Further, the planetary gear PR, the planetarygear unit PU and the counter gear 50 are provided coaxially with theinput shaft 20.

[0262] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₅ with reference to FIGS. 19, 20 and21 on the basis of the structure described above. It should be notedthat, in the velocity diagram shown in FIG. 21, the vertical axisindicates the rotation speed of each of the rotation elements, and thehorizontal axis indicates and corresponds to a gear ratio of each of therotation elements. Further, in the portion for the planetary gear unitPU in the velocity diagram, the vertical axis of the endmost portion inthe horizontal direction (the right side in FIG. 21) corresponds to thesun gear S3, and from there toward the left side of the drawing, thevertical axes correspond to the carrier CR2, the ring gear R2, and thesun gear S2.

[0263] As shown in FIG. 19, the rotation of the input shaft 20 is inputto the sun gear S2 in accordance with the engagement of the clutch C1.The rotation of the input shaft 20 is input to the carrier CR2 inaccordance with the engagement of the clutch C2, and the carrier CR2 hasits rotation selectively fixed in accordance with braking of the brakeB2, and is restricted to rotating in one direction by the one-way clutchF3. Further, the sun gear S3 can have its rotation selectively fixed inaccordance with braking of the brake B1.

[0264] On the other hand, the sun gear S1 is connected to the inputshaft 20, the rotation of the input shaft 20 is input to the sun gearS1, and the carrier CR1 is connected to the case 3 b and has itsrotation fixed. As a result, the ring gear R1 is rotated at a reducedspeed. Further, the reduced rotation of the ring gear R1 is input to thesun gear S3 in accordance with the engagement of the clutch C3.

[0265] Further, the rotation of the ring gear R2 is output to thecounter gear 50, and is output to the driven wheel (not shown) via thecounter shaft portion 4 and the differential portion 5 (refer to FIG.1).

[0266] In the forward first speed in a drive (D) range, as shown in FIG.20, the clutch C1 and the one-way clutch F3 are engaged. Accordingly, asshown in FIG. 21, the rotation of the input shaft 20 is input to the sungear S2 via the clutch C1, and the rotation of the carrier CR2 isrestricted to one direction (a forward rotation direction), that is, thecarrier CR2 is prevented from being backward rotated, thereby beingplaced in a fixed state. Further, the rotation of the input shaft 20input to the sun gear S2 is output to the ring gear R2 via the fixedcarrier CR2, and a forward rotation that corresponds to the forwardfirst speed is output from the counter gear 50. In this case, whenengine brake (coasting) takes place, the forward first speed state ismaintained such that the brake B2 is engaged so as to fix the carrierCR2, and prevent the carrier CR2 from rotating forward. Further, in theforward first speed, the one-way clutch F3 prevents the carrier CR2 fromrotating backward and allows it to rotate forward. Accordingly, it ispossible to smoothly achieve the forward first speed, for example, at atime of changing from a non-running range to a running range, as aresult of automatic engagement of the one-way clutch.

[0267] In the forward second speed in the drive (D) range, as shown inFIG. 20, the clutch C1 is engaged, and the brake B1 is engaged.Accordingly, as shown in FIG. 21, the rotation of the input shaft 20 isinput to the sun gear S2 via the clutch C1, and the sun gear S3 is fixedin accordance with the engagement of the brake B1. Accordingly, thecarrier CR2 rotates at a slightly reduced speed, the rotation of theinput shaft 20 input to the sun gear S2 is output to the ring gear R2via the carrier CR2 rotating at the reduced speed, and a forwardrotation that corresponds to the forward second speed is output from thecounter gear 50.

[0268] In the forward third speed in the drive (D) range, as shown inFIG. 20, the clutch C1 and the clutch C3 are engaged. Accordingly, asshown in FIG. 21, the rotation of the input shaft 20 is input to the sungear S2 via the clutch C1. Further, the ring gear R1 is rotated at areduced speed by the rotation of the input shaft input to the sun gearS1 and the fixed carrier CR1. The reduced rotation of the ring gear R1is output to the sun gear S3 via the clutch C3 and the transmissionmember 240. Accordingly, the carrier CR2 is rotated at a slightly largerreduced speed than the reduced rotation of the sun gear S3 in accordancewith the rotation of the input shaft 20 input to the sun gear S2 and thereduced rotation of the sun gear S3. Further, the rotation of the inputshaft 20 input to the sun gear S2 is output to the ring gear R2 via thecarrier CR2 rotating at the reduced speed, and the forward rotation thatcorresponds to the forward third speed is output from the counter gear50. In this case, at this time, because the sun gear S3 and the ringgear R1 rotate at the reduced speed, the transmission member 240transmits a comparatively large torque.

[0269] In the forward fourth speed in the drive (D) range, as shown inFIG. 20, the clutch C1 and the clutch C2 are engaged. Accordingly, asshown in FIG. 21, the rotation of the input shaft 20 is input to the sungear S2 via the clutch C1 and to the carrier CR2 via the clutch C2.Thus, the rotation of the input shaft 20 is output as it is to the ringgear R2 in accordance with the rotation of the input shaft 20 input tothe sun gear S2 and the rotation of the input shaft 20 input to thecarrier CR2, that is, in a directly connected state, and a forwardrotation that corresponds to the forward fourth speed is output from thecounter gear 50.

[0270] In the forward fifth speed in the drive (D) range, as shown inFIG. 20, the clutch C2 and the clutch C3 are engaged. Accordingly, asshown in FIG. 21, the rotation of the input shaft 20 is input to thecarrier CR2 via the clutch C2. Further, the ring gear R1 is rotated at areduced speed by the rotation of the input shaft 20 input to the sungear S1 and the fixed carrier CR1, and the reduced rotation of the ringgear R1 is output to the sun gear S3 via the clutch C3 and thetransmission member 240. Accordingly, an increased rotation is output tothe ring gear R2 by the reduced rotation of the sun gear S3 and thecarrier CR2 to which the rotation of the input shaft 20 is input, and aforward rotation that corresponds to the forward fifth speed is outputfrom the counter gear 50. In this case, at this time, as with theforward third speed state described above, because the sun gear S3 andthe ring gear R1 rotate at the reduced speed, the transmission member240 transmits a comparatively large torque.

[0271] In the forward sixth speed in the drive (D) range, as shown inFIG. 20, the clutch C2 is engaged, and the brake B1 is engaged.Accordingly, as shown in FIG. 21, the rotation of the input shaft 20 isinput to the carrier CR2 via the clutch C2, and the sun gear S3 is fixedin accordance with the engagement of the brake B1. Thus, the rotationbecomes an increased rotation (larger than the forward fifth speeddescribed above) in accordance with the rotation of the input shaft 20input to the carrier CR2 and the fixed sun gear S3, and the increasedrotation is output to the ring gear R2. Accordingly, a forward rotationthat corresponds to the forward sixth speed is output from the countergear 50.

[0272] In the backward first speed in the reverse (R) range, as shown inFIG. 20, the clutch C3 is engaged, and the brake B2 is engaged.Accordingly, as shown in FIG. 21, the ring gear R1 rotates at a reducedspeed as a result of the rotation of the input shaft 20 input to the sungear S1 and the fixed carrier CR1. Further, the reduced rotation of thering gear R1 is output to the sun gear S3 via the clutch C3 and thetransmission member 240. Further, the carrier CR2 is fixed in accordancewith the engagement of the brake B2. Accordingly, the rotation is outputto the ring gear R2 as reverse rotation in accordance with the reducedrotation of the sun gear S3 and the fixed carrier CR2, and a reverserotation that corresponds to the backward first speed is output from thecounter gear 50. In this case, at this time, because the sun gear S3 andthe ring gear R1 rotate at the reduced speed as in the state of theforward third speed and the forward fifth speed, the transmission member240 transmits a comparatively large torque.

[0273] In the parking (P) range and the neutral (N) range, inparticular, the clutch C1, the clutch C2 and the clutch C3 aredisengaged, and power transmission between the input shaft 20 and thecounter gear 50 is in an interrupted state, so that the entire automatictransmission 25 is in a slipping state (a neutral state).

[0274] As described above, with the automatic transmission 1 ₅ having anautomatic speed change mechanism 2 ₅, the planetary gear PR, the clutchC3 and the transmission member 240 which correspond to the reducedrotation output unit are arranged at one side (the left side in FIG. 19)in the axial direction of the planetary gear unit PU, the clutch C1 andthe clutch C2 are arranged at the other side (the right side in FIG. 19)in the axial direction of the planetary gear unit PU, and the countergear 50 that corresponds to the output member is arranged between theclutch C1, the clutch C2 and the planetary gear unit PU. Accordingly, itis possible to position, in particular, the planetary gear PR and theplanetary gear unit PU close to each other, and it is possible to makethe length of the transmission member 240 that transmits the reducedrotation comparatively short in the axial direction. Thus, it ispossible to achieve a compact structure and weight saving for theautomatic transmission 1 ₅, and it is possible to make the inertia (theinertia force) small in accordance with the weight saving of thetransmission member 240. Accordingly, it is possible to improve thecontrollability of the automatic transmission 1 ₅, and it is possible toreduce the generation of shift shock.

[0275] Further, because the clutch C2 is connected to the carrier CR2via the outer peripheral side of the clutch C1, it is possible toprevent the member that connects each of the rotation elements frombeing complicated, and it is possible to make the automatic transmission1 ₅ compact.

[0276] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, cannot have itsdiameter enlarged toward the outer peripheral side. However, it ispossible to ensure that the hydraulic servo 262, and more particularly,the pressure receiving area of the oil chamber 262 a for the hydraulicservo 262, is large at the inner peripheral side by providing thehydraulic servo 262 on the input shaft 20 (in comparison with the case,for example, of provision on the boss portion 3 c), and it is possibleto increase the capacity of the clutch C1.

[0277] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case that the automatic transmission 1 ₅ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and it is possible to improve the ease of mountingof the automatic transmission 1 ₅.

[0278] Further, the clutch C3 connects and disconnects the output of thereduced rotation. Therefore, by disengaging the clutch C3, it ispossible to make the rotation of the input shaft input to the sun gearS1 rotate idly using the planetary gear PR and, more particularly, usingthe ring gear R1, while, at the same time, it is possible to selectivelyoutput the reduced rotation to the sun gear S3. Accordingly, it ispossible to directly fix the carrier CR1 to the case 3, or the like,without providing a brake. It is also possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₅. Further,as a brake fixing the carrier CR1 is not provided, it is possible toarrange the brake B1 that selectively engages the sun gear S3 at theouter peripheral side of the planetary gear PR.

[0279] Further, because the hydraulic servo 262 is provided on the inputshaft 20, it is possible to supply the oil to the oil chamber 262 a ofthe hydraulic servo 262 by preventing the oil from leaking from the case3 by using the pair of sealing rings 281, and supplying the oil to theoil passages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 262. Further, the hydraulic servos 261, 265 can supplyoil from the boss portions 3 c, 3 d that extend from the case 3, forexample, without passing the oil through other members, that is, the oilcan be supplied by respectively arranging the pairs of sealing rings280, 282. Accordingly, it is possible to supply the oil to the hydraulicservos 262, 261, 265 by simply providing the pairs of sealing rings 281,280, 282. It is also possible to minimize the sliding resistance thatresults from the sealing ring whereby it is possible to improve theefficiency of the automatic transmission 1 ₅.

[0280] Further, because the friction disk 275 is arranged at an outerperipheral side of the planetary gear PR in the diametrical direction,it is possible to make the automatic transmission 1 ₅ compact in theaxial direction. Because it is possible to arrange the planetary gear PRand the planetary gear unit PU adjacent to each other by arranging theplanetary gear PR between the hydraulic servo 265 of the clutch C3 andthe planetary gear unit PU in the axial direction (as the hydraulicservo 265 of the clutch C3 is not provided between the planetary gear PRand the planetary gear unit PU), it is possible to make the transmissionmember 240 comparatively short. Accordingly, it is possible to achieve acompact structure and weight saving in the automatic transmission 1 ₅,and it is possible to make the inertia (the inertia force) small. As aresult, it is possible to improve the controllability of the automatictransmission 1 ₅, and to reduce the generation of shift shock.

[0281] In addition, because the planetary gear PR is the double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case that the gearratio of the automatic transmission 1 ₅ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₅compact.

[0282] Additionally, as the planetary gear unit PR is structured suchthat it includes the sun gear S1 that corresponds to the input rotationelement, the carrier CR1 that corresponds to the fixed element, and thering gear R1 that corresponds to the output rotation element, it ispossible to output the rotation of the input shaft 20 as the reducedrotation.

[0283] Further, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2. Accordingly, the configuration makesit possible to achieve, for example, the six forward speeds and the onebackward speed, while, at the same time, it is possible to position theplanetary gear PR and the planetary gear unit PU close to each other. Asa result, it is possible to make the transmission member 240 thattransmits the reduced rotation comparatively short.

[0284] Because the one-way clutch F3, which is positioned in parallelwith the brake B2 and restricts the rotation of the carrier CR2 to onedirection, it is possible to achieve, for example, the forward firstspeed at a time of normal running by engagement of the clutch C1 and theone-way clutch F3. As a result, it is possible to smoothly achieve theforward first speed, for example, at a time of changing from anon-running range to a running range.

[0285] As the brake B2 and the one-way clutch F3 are arranged at theouter peripheral side of the planetary gear unit PU, it is possible tomake the portion in which the clutches C1, C2 are arranged compact inthe axial direction in comparison with the case, for example, where theone-way clutch F3 is arranged adjacent to the clutch C2 (particularlyfor restricting the rotation of the hub member 223 in one direction). Asa result, it is possible to position the counter gear 50 closer to thetorque converter side. Thus, it is possible to position the gear 51 ofthe counter shaft 52 closer to the torque converter side and to make thecounter shaft portion 4 compact in the axial direction.

[0286] Further, as shown in the velocity diagram, the configurationmakes it possible to achieve the six forward speeds and the one backwardspeed, while it is also possible to arrange the planetary gear PR andthe planetary gear unit PU close to one another, and make thetransmission member 240, that transmits the reduced rotation,comparatively short. Accordingly, it is possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₅, and tomake the inertia (the inertia force) small. As a result, it is possibleto improve the controllability of the automatic transmission 1 ₅ and itis possible to reduce the generation of shift shock.

[0287] Further, the configuration can realize the six forward speeds andthe one backward speed, and both the clutches C1, C2 are engaged in theforward fourth speed, that is, the directly connected state isestablished in the forward fourth speed. As a result, it is possible toset the gear ratio in the forward fifth speed and the forward sixthspeed so that it is high in the case, in particular, of a vehiclerunning at a high speed for which the mounting has been executed, tomake the engine speed low, and to contribute to quietness of the vehiclewhen running at high speed.

[0288] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Therefore, it is possible to mount theautomatic transmission 1 ₅, for example, in the FF vehicle.

[0289] Hereinafter, a description will be given, with reference to FIG.22, of a sixth embodiment that is a partial modification of the fifthembodiment. In this case, in the sixth embodiment, with the exception ofthe partially modified portions, the same reference numerals denote thesame elements as those of the first and second embodiments, and adescription thereof will be omitted.

[0290] As shown in FIG. 22, an automatic speed change mechanism 2 ₆ ofthe automatic transmission 1 according to the sixth embodiment isstructured such that the input side and the output side are reversedwith respect to the automatic speed change mechanism 2 ₅ (refer to FIG.19) in accordance with the fifth embodiment. Further, the operations inthe forward first speed, the forward sixth speed, and the backward firstspeed, are the same (refer to FIGS. 20 and 21).

[0291] Therefore, in the same manner as the fifth embodiment, in theautomatic transmission 1 ₆ having the automatic speed change mechanism 2₆, the planetary gear PR, the clutch C3 and the transmission member 240which correspond to the reduced rotation output unit are arranged at oneside (the right side in FIG. 22) in the axial direction of the planetarygear unit PU, the clutch C1 and the clutch C2 are arranged at the otherside (the left side in FIG. 22) in the axial direction of the planetarygear unit PU, and the counter gear 50, that corresponds to the outputmember, is arranged between the clutch C1, the clutch C2 and theplanetary gear unit PU. As a result, it is possible to position, inparticular, the planetary gear PR and the planetary gear unit PU closeto each other, and it is possible to make the length of the transmissionmember 240 that transmits the reduced rotation comparatively short inthe axial direction. Accordingly, it is possible to achieve a compactstructure and weight saving for the automatic transmission 1 ₆ and tomake the inertia (the inertia force) small in accordance with the weightsaving of the transmission member 240. Thus, it is possible to improvethe controllability of the automatic transmission 1 ₆ and to reduce thegeneration of shift shock.

[0292] Further, because the clutch C2 is connected to the carrier CR2via the outer peripheral side of the clutch C1, it is possible toprevent the member that connects each of the rotation elements frombeing complicated and to make the automatic transmission 1 ₆ compact.

[0293] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, can not haveits diameter enlarged toward the outer peripheral side. However, it ispossible to ensure that the hydraulic servo 262, and more particularly,the pressure receiving area of the oil chamber 262 a for the hydraulicservo 262 is large at the inner peripheral side by providing thehydraulic servo 262 on the input shaft 20 (in comparison with the case,for example, of provision on the boss portion 3 c), and it is possibleto increase the capacity of the clutch C1.

[0294] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case that the automatic transmission 1 ₆ is mountedin the FF vehicle, (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with, for example, by avehicle body member, and it is possible to improve the ease of mountingof the automatic transmission 1 ₆.

[0295] Further, the clutch C3 connects and disconnects the output of thereduced rotation. Accordingly, by disengaging the clutch C3, it ispossible to make the rotation of the input shaft that is input to thesun gear S1 rotate idly using the planetary gear PR and, moreparticularly, using the ring gear R1, while at the same time it ispossible to selectively output the reduced rotation to the sun gear S3.Accordingly, it is possible to directly fix the carrier CR1 to the case3, or the like, without providing a brake, and it is possible to achievea compact structure and weight saving for the automatic transmission 1₆. Further, because a brake fixing the carrier CR1 is not provided, itis possible to arrange the brake B1 that can selectively brake the sungear S3 at the outer peripheral side of the planetary gear PR.

[0296] Because the hydraulic servo 262 is provided on the input shaft20, it is possible to supply the oil to the oil chamber 262 a of thehydraulic servo 262 and prevent the oil from leaking from the case 3 byusing the pair of sealing rings 281, and to supply the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, without, forexample, providing a sealing ring between the input shaft 20 and thehydraulic servo 262. Further, the hydraulic servos 261, 265 can supplythe oil from the boss portions 3 c, 3 d that extend from the case 3, forexample, without passing it through other members, that is, the oil canbe supplied by respectively arranging the pair of sealing rings 280,282. Accordingly, it is possible to supply the oil to the hydraulicservos 262, 261, 265 by simply providing the respective pairs of sealingrings 281, 280, 282, and it is possible to minimize the slidingresistance resulting from the sealing rings. As a result, it is possibleto improve the efficiency of the automatic transmission 1 ₆.

[0297] In addition, because the friction disk 275 is arranged at anouter peripheral side of the planetary gear PR in the diametricaldirection, it is possible to make the automatic transmission 1 ₆ compactin the axial direction. Further, as it is possible to arrange theplanetary gear PR and the planetary gear unit PU adjacent to each otherby arranging the planetary gear PR between the hydraulic servo 265 ofthe clutch C3 and the planetary gear unit PU in the axial direction(because the hydraulic servo 265 of the clutch C3 is not providedbetween the planetary gear PR and the planetary gear unit PU), it ispossible to make the transmission member 240 comparatively short.Accordingly, it is possible to achieve a compact structure and weightsaving in the automatic transmission 1 ₆ as well as make the inertia(the inertia force) small. Thus, it is possible to improve thecontrollability of the automatic transmission 1 ₆ and to reduce thegeneration of shift shock.

[0298] Further, as the planetary gear PR is a double pinion planetarygear, it is possible to output the rotation of the input shaft 20 as thereduced rotation. Further, even in the case that the gear ratio of theautomatic transmission 1 ₆ is set favorably, the high speed rotation canbe restricted without making each of the rotation elements of theplanetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₆compact.

[0299] In addition, because the planetary gear unit PR is structured toinclude the sun gear S1, that corresponds to the input rotation element,the carrier CR1, that corresponds to the fixed element, and the ringgear R1, that corresponds to the output rotation element, it is possibleto output the rotation of the input shaft 20 as the reduced rotation.

[0300] Additionally, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2. Accordingly, the configuration makesit possible to realize, for example, the six forward speeds and the onebackward speed, while it is also possible to position the planetary gearPR and the planetary gear unit PU close to each other, and make thetransmission member 240 that transmits the reduced rotationcomparatively short.

[0301] Further, the one-way clutch F3 is provided in parallel to thebrake B2 and restricts the rotation of the carrier CR2 to one direction.Accordingly, it is possible to achieve, for example, the forward firstspeed at a time of normal running by engagement of the clutch C1 and theone-way clutch F3, so that it is possible to smoothly achieve theforward first speed, for example, at a time of changing from anon-running range to a running range.

[0302] Further, because the brake B2 and the one-way clutch F3 arearranged at the outer peripheral side of the planetary gear unit PU, itis possible to make the portion in which the clutches C1, C2 arearranged compact in the axial direction in comparison with the case, forexample, where the one-way clutch F3 is arranged adjacent to the clutchC2 (particularly for restricting the rotation of the hub member 223 inone direction). Therefore, it is possible to position the counter gear50 close to the torque converter. Accordingly, it is possible toposition the gear 51 of the counter shaft 52 close to the torqueconverter, and it is possible to make the counter shaft portion 4compact in the axial direction.

[0303] Further, as shown in the velocity diagram of FIG. 21, it ispossible to arrange the planetary gear PR and the planetary gear unit PUclose to each other while achieving the six forward speeds and the onebackward speed and to make the transmission member 240 that transmitsthe reduced rotation comparatively short. Thus, it is possible toachieve a compact structure and weight saving in the automatictransmission 1 ₆ and to make the inertia (the inertia force) small.Accordingly, it is possible to improve the controllability of theautomatic transmission 1 ₆ and to reduce the generation of shift shock.

[0304] Further, the configuration makes it possible to realize the sixforward speeds and the one backward speed, and both the clutches C1, C2are engaged in the forward fourth speed, that is, the directly connectedstate is established in the forward fourth speed. Accordingly, it ispossible to set the gear ratio in the forward fifth speed and theforward sixth speed so that it is high. In the case, in particular, of avehicle running at a high speed for which mounting has been executed, itis possible to make the engine speed low and to contribute to quietnessof the vehicle when running at high speed.

[0305] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Accordingly, it is possible to mount theautomatic transmission 1 ₆, for example, in the FF vehicle.

[0306] Hereinafter, a description will be given, with reference to FIGS.23 to 25, of a seventh embodiment that is a partial modification of thefifth embodiment. It should be noted that, in the seventh embodiment,with the exception of the partially modified portions, the samereference numerals denote the same elements as those of the fifthembodiment and a description thereof will be omitted.

[0307] As shown in FIG. 23, an automatic speed change mechanism 2 ₇ ofthe automatic transmission 1 ₇ in accordance with the seventh embodimentis structured such that the arrangement of the planetary gear PR and theclutch C3 is changed with respect to the automatic speed changemechanism 2 ₅ in accordance with the fifth embodiment (refer to FIG.19).

[0308] In the automatic speed change mechanism 2 ₇, the clutch (thethird clutch) C3 is arranged at the opposite side (the left side in thedrawing) of the planetary gear (the reduced rotation output unit, thespeed reduction planetary gear) PR to the planetary gear unit PU. Aninner peripheral side of a drum-like member 331 of the clutch C3 isspline engaged to the friction disk 275. Further, the drum-like member331 of the clutch C3 is connected to the input shaft 20.

[0309] On the other hand, the sun gear (the input rotation element, thefirst sun gear) S1 is rotatably supported by the input shaft 20, and isconnected to a hub member 332. The friction disk 275 is spline engagedto an outer peripheral side of a leading end portion of the hub member332. Further, the carrier (the fixed element, the first carrier) CR1 isfixed and supported by the case 3 b such that a fixed member 330 isconnected to the side plate thereof. Further, the friction disk 274 ofthe brake B1 is spline engaged to the outer peripheral side of the ringgear (the output rotation element, the first ring gear) R1, atransmission member 340 is connected to the ring gear R1, and the sungear S3 is connected via the transmission member 340.

[0310] The oil chamber 265 a of the hydraulic servo 265 for the clutchC3 communicates with oil passages 20 c, 20 d formed in the input shaft20, and the oil passage 20 c communicates with an oil passage 293 of theboss portion 3 d in the case 3. Further, the oil passage 293communicates with the hydraulic control apparatus (not shown). In otherwords, the hydraulic servo 265 is arranged on the input shaft 20, an oilpassage from the hydraulic control apparatus (not shown) to the oilchamber 265 a is configured by a pair of sealing rings 283 that seal aportion between the boss portion 3 d of the case 3 and the input shaft20.

[0311] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₇ with reference to FIGS. 23, 24 and25 on the basis of the structure described above. Note that, in the samemanner as the fifth embodiment described above, in the velocity diagramshown in FIG. 25, the vertical axis indicates a rotation speed of eachof the rotation elements, and the horizontal axis indicates andcorresponds to a gear ratio of each of the rotation elements. Further,in the portion of the velocity diagram for the planetary gear unit PU,the vertical axis at the endmost portion in the horizontal direction(the right side in FIG. 25) corresponds to the sun gear S3, and fromthere toward the left side of the drawing, the vertical axes correspondto the carrier CR2, the ring gear R2 and the sun gear S2, respectively.

[0312] As shown in FIG. 23, the rotation of the input shaft 20 is inputto the sun gear S1 in accordance with the engagement of the clutch C3.Further, the rotation of the carrier CR1 is fixed with respect to thecase 3, and the ring gear R1 described above rotates at a reduced speedon the basis of the rotation of the input shaft 20 input to the sun gearS1. In other words, the reduced rotation of the ring gear R1 is input tothe sun gear S3 via the transmission member 340 in accordance with theengagement of the clutch C3.

[0313] Accordingly, as shown in FIGS. 24 and 25, in the planetary gearPR, in the forward third speed, the forward fifth speed and the backwardfirst speed, the clutch C3 is engaged, whereby the rotation of the inputshaft 20 is input to the sun gear S1, the reduced rotation is output tothe ring gear R3 by the fixed carrier CR1, and the reduced rotation isinput to the sun gear S3 via the transmission member 340. At this time,because the ring gear R1 and the sun gear S3 are rotated at the reducedspeed, the transmission member 340 transmits a comparatively largetorque. On the other hand, in the forward first speed, the forwardsecond speed, the forward fourth speed and the forward sixth speed, therotation of the sun gear S3 is input to the ring gear R1 via thetransmission member 340 and the clutch C3 is disengaged. Accordingly,the sun gear S1 is rotated on the basis of the rotation of the ring gearR1 in each of the shift speeds and the fixed carrier CR1 as shown inFIG. 25.

[0314] Note that, the operations other than that of the planetary gearPR are the same as those of the fifth embodiment described above.Accordingly, a description thereof will be omitted.

[0315] As described above, with the automatic transmission 2 ₇, theplanetary gear PR, the clutch C3, and the transmission member 340 whichcorrespond to the reduced rotation output unit are arranged at one side(the left side in FIG. 23) in the axial direction of the planetary gearunit PU, the clutch C1 and the clutch C2 are arranged at the other side(the right side in FIG. 23) in the axial direction of the planetary gearunit PU, and the counter gear 50, that corresponds to the output member,is arranged between the clutch C1, the clutch C2 and the planetary gearunit PU. Accordingly, it is possible to position, in particular, theplanetary gear PR and the planetary gear unit PU close to each other,and it is possible to make the length of the transmission member 340,that transmits the reduced rotation, comparatively short in the axialdirection. Accordingly, it is possible to achieve a compact structureand weight saving for the automatic transmission 1 ₇ to make the inertia(the inertia force) small in accordance with the weight saving of thetransmission member 340. Accordingly, it is possible to improve thecontrollability of the automatic transmission 1 ₇ and to reduce thegeneration of shift shock.

[0316] Further, because the clutch C2 is connected to the carrier CR2via the outer peripheral side of the clutch C1, it is possible toprevent the member that connects each of the rotation elements frombeing complicated and to make the automatic transmission 1 ₇ compact.

[0317] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, its diametercannot be enlarged toward the outer peripheral side. However, it ispossible to ensure that the hydraulic servo 262, and more particularly,the pressure receiving area of the oil chamber 262 a of the hydraulicservo 262, is large at the inner peripheral side by providing thehydraulic servo 262 on the input shaft 20 (in comparison with the case,for example, of provision on the boss portion 3 c), and it is possibleto increase the capacity of the clutch C1.

[0318] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case where the automatic transmission 1 ₇ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and it is possible to improve the ease of mountingof the automatic transmission 1 ₇.

[0319] Further, for example, as disclosed in Japanese Patent Laid-OpenPublication No. 2001-263438, in the case that the clutch C3 isinterposed between the ring gear R1 and the sun gear S3, it is necessaryto connect and disconnect the reduced rotation, so that the structurebecomes comparatively large, and a distance between the planetary gearPR and the planetary gear unit PU is lengthened. However, as a result ofinterposition between the input shaft 20 and the sun gear S1, thereduced rotation output from the ring gear R1 of the planetary gear PRis connected and disconnected by connecting and disconnecting therotation of the input shaft 20 using the clutch C3. Accordingly, it ispossible to make the clutch C3 compact, and to arrange the planetarygear PR and the planetary gear unit PU at comparatively close positions.Therefore, it is possible to make the automatic transmission 1 ₇compact.

[0320] Further, as the hydraulic servos 262, 265 are provided on theinput shaft 20, it is possible to supply the oil to the oil chambers 262a, 265 a of the hydraulic servos 262, 265 by preventing the oil fromleaking from the case 3 using the pairs of sealing rings 281, 283, andby supplying the oil to the oil passages 20 a, 20 b, 20 c, 20 d providedwithin the input shaft 20, for example, without providing a sealing ringbetween the input shaft 20 and the hydraulic servos 262, 265. Further,the hydraulic servo 261 can supply the oil from the boss portion 3 cthat extends from the case 3, for example, without passing it throughother members, that is, the oil can be supplied by respectivelyarranging the pair of sealing rings 280. Accordingly, it is possible tosupply the oil to the hydraulic servos 262, 261, 265 by simply arrangingthe respective pairs of sealing rings 281, 280, 283 and to minimize thesliding resistance that results from the sealing ring. As a result, itis possible to improve the efficiency of the automatic transmission 1 ₇.Further, the hydraulic servos 262, 265 are arranged on the input shaft20. However, as they are arranged separately at one end side (the rightside in FIG. 23) and the other end side (the left side in FIG. 23) ofthe input shaft 20, respectively, it is not necessary to provide thehydraulic passages (for example, the oil passage 20 a and the oilpassage 20 c) for the hydraulic servo within the input shaft 20 suchthat they overlap. Accordingly, it is possible to narrow the input shaft20 and to further compact the automatic transmission 1 ₇.

[0321] Additionally, because the planetary gear PR is a double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case where the gearratio of the automatic transmission 1 ₇ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to further compact the automatictransmission 1 ₇.

[0322] Further, as the planetary gear PR is structured to include thesun gear S1, that corresponds to the input rotation element, the carrierCR1, that corresponds to the fixed element, and the ring gear R1, thatcorresponds to the output rotation element, it is possible to output therotation of the input shaft 20 as the reduced rotation.

[0323] In addition, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2. Accordingly, it is possible to arrangethe planetary gear PR and the planetary gear unit PU close to each otherso as to achieve, for example, the six forward speeds and the onebackward speed. Thus, it is possible to make the transmission member 340that transmits the reduced rotation comparatively short.

[0324] Further, because the one-way clutch F3 is provided in parallel tothe brake B2 and restricts the rotation of the carrier CR2 to onedirection, it is possible to achieve the forward first speed, forexample, at a time of normal running by engagement of the clutch C1 andthe one-way clutch F3. Accordingly, it is possible to smoothly achievethe forward first speed, for example, at a time of changing from anon-running range to a running range.

[0325] Further, as the brake B2 and the one-way clutch F3 are arrangedat the outer peripheral side of the planetary gear unit PU, it ispossible to make the portion in which the clutches C1, C2 are arrangedcompact in the axial direction in comparison with the case, for example,where the one-way clutch F3 is arranged adjacent to the clutch C2(particularly for restricting the rotation of the hub member 223 in onedirection). As a result, it is possible to position the counter gear 50closer to the torque converter side. Therefore, it is possible toposition the gear 51 of the counter shaft 52 closer to the torqueconverter side and to make the counter shaft portion 4 compact in theaxial direction.

[0326] Further, as shown in the velocity diagram, the configuration isable to realize the six forward speeds and the one backward speed, whileit is also possible to position the planetary gear PR and the planetarygear unit PU close to each other, and make the transmission member 340,that transmits the reduced rotation, comparatively short. Accordingly,it is possible to achieve a compact structure and weight saving of theautomatic transmission 1 ₇ and to make the inertia (the inertia force)small. As a result, it is possible to improve the controllability of theautomatic transmission 1 ₇ and to reduce the generation of shift shock.

[0327] Further, the configuration can realize the six forward speeds andthe one backward speed, and both clutches C1, C2 are engaged in theforward fourth speed, that is, the directly connected state isestablished in the forward fourth speed. Accordingly, it is possible toset the gear ratio in the forward fifth speed and the forward sixthspeed so that it is high. In the case, in particular, of a vehiclerunning at a high speed for which mounting has been executed, it ispossible to make the engine speed low and to contribute to quietness ofthe vehicle when running at high speed.

[0328] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Accordingly, it is possible to mount theautomatic transmission 1 ₇, for example, in the FF vehicle.

[0329] Hereinafter, a description will be given, with reference to FIGS.26 to 28, of an eighth embodiment that is a partial modification of thefifth embodiment. In the eighth embodiment, with the exception ofpartially modified portions, the same reference numerals denote the sameelements as those of the fifth embodiment and a description thereof willbe omitted.

[0330] As shown in FIG. 26, an automatic speed change mechanism 2 ₈ ofthe automatic transmission 1 ₈ in accordance with the eighth embodiment,as compared to the automatic speed change mechanism 2 ₅ in accordancewith the fifth embodiment (refer to FIG. 19), is structured such thatthe brake (the third brake) B3 is provided instead of the clutch C3, andthe carrier (the fixed element, the first carrier) CR1 of the planetarygear PR can be selectively engaged by the brake B3.

[0331] In the automatic speed change mechanism 2 ₇, the brake B3 isarranged at the opposite side (the left side in the drawing) of theplanetary gear (the reduced rotation output unit, the speed reductionplanetary gear) PR to the planetary gear unit PU. The brake B3 has ahydraulic servo 266, a friction disk 276 and a hub member 432. Thehydraulic servo 266 has a piston member 266 b, that presses the frictiondisk 276, a cylinder portion 266 e formed in a part of the case 3 b, anoil chamber 266 a formed between the piston member 266 b and thecylinder portion 266 e and sealed by sealing rings 266 f, 266 g, areturn spring 266 c, that energizes the piston member 266 b in thedirection of the oil chamber 266 a, and a return plate 266 d, thatreceives the energy of the return spring 266 c.

[0332] The hub member 432 of the brake B3 is connected to a side plateat one side of the carrier CR1. The other side plate 434 of the carrierCR1 is rotatably supported by the input shaft 20. The sun gear (theinput rotation element, the first sun gear) S1 is connected to the inputshaft 20. Further, the friction disk 274 of the brake B1 is splineengaged to an outer peripheral side of the ring gear (the outputrotation element, the first ring gear) R1, a transmission member 440 isconnected to the ring gear R1, and the sun gear S3 is connected via thetransmission member 440.

[0333] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₈ with reference to FIGS. 26, 27 and28 on the basis of the structure described above. Note that, in the samemanner as the fifth embodiment described above, in the velocity diagramshown in FIG. 28, the vertical axis indicates a rotation speed of eachof the rotation elements, and the horizontal axis indicates andcorresponds to a gear ratio of each of the rotation elements. Further,in the portion for the planetary gear unit PU of the velocity diagram,the vertical axis of the endmost portion in the horizontal direction(the right side in FIG. 28) corresponds to the sun gear S3, and fromthere toward the left side of the drawing, the vertical axes correspondto the carrier CR2, the ring gear R2 and the sun gear S2.

[0334] As shown in FIG. 26, the carrier CR1 is fixed to the case 3 b bybraking of the brake B3. Further, the rotation of the input shaft 20 isinput to the sun gear S1, and the ring gear R1, described above, isrotated at a reduced speed on the basis of the rotation of the inputshaft 20 input to the sun gear S1, as a result of fixing of the carrierCR1. In other words, the reduced rotation of the ring gear R1 is inputto the sun gear S3 via the transmission member 440 due to the braking ofthe brake B3.

[0335] Accordingly, as shown in FIGS. 27 and 28, in the planetary gearPR, in the forward third speed, the forward fifth speed and the backwardfirst speed, the carrier CR1 is fixed by braking of the brake B3,whereby the reduced rotation is output to the ring gear R3 in accordancewith the rotation of the sun gear S1 to which the rotation of the inputshaft 20 is input, and the reduced rotation is input to the sun gear S3via the transmission member 440. At this time, as the ring gear R1 andthe sun gear S3 are rotated at the reduced speed, the transmissionmember 440 transmits a comparatively large torque. On the other hand, inthe forward first speed, the forward second speed, the forward fourthspeed and the forward sixth speed, the rotation of the sun gear S3 isinput to the ring gear R1 via the transmission member 440 and the brakeB3 is disengaged. Accordingly, the carrier CR1 is rotated on the basisof the rotation of the ring gear R1 in each of the respective shiftspeeds and the sun gear S1 that has the rotation of the input shaft 20,as shown in FIG. 28.

[0336] Note that, because the operations other than that of theplanetary gear PR are the same as those of fifth embodiment describedabove, a description thereof will be omitted.

[0337] As described above, with the automatic transmission 2 ₈, theplanetary gear PR, the brake B3 and the transmission member 440 whichcorrespond to the reduced rotation output unit are arranged at one side(the left side in FIG. 26) in the axial direction of the planetary gearunit PU, the clutch C1 and the clutch C2 are arranged at the other side(the right side in FIG. 26) in the axial direction of the planetary gearunit PU, and the counter gear 50 that corresponds to the output memberis arranged between the clutch C1, the clutch C2 and the planetary gearunit PU. Accordingly, it is possible to position, in particular, theplanetary gear PR and the planetary gear unit PU close to each other andthereby make the length of the transmission member 340, that transmitsthe reduced rotation, comparatively short in the axial direction.Accordingly, it is possible to achieve a compact structure and weightsaving for the automatic transmission 1 ₈ and to make the inertia (theinertia force) small in accordance with the weight saving of thetransmission member 440. As a result, it is possible to improve thecontrollability of the automatic transmission 1 ₈ and to reduce thegeneration of shift shock.

[0338] Further, because the clutch C2 is connected to the carrier CR2through the outer peripheral side of the clutch C1, it is possible toprevent the member that connects each of the rotation elements frombeing complicated and to make the automatic transmission 1 ₈ compact.

[0339] Further, the clutch C1 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, cannot have itsdiameter enlarged at the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 262 and, more particularly, thepressure receiving area of the oil chamber 262 a for the hydraulic servo262, is large at the inner peripheral side by providing the hydraulicservo 262 on the input shaft 20 (in comparison with the case, forexample, of provision on the boss portion 3 c), and to increase thecapacity of the clutch C1.

[0340] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4 or the like) compact, inparticular, in the case where the automatic transmission 1 ₈ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and to improve the ease of mounting of theautomatic transmission 1 ₈.

[0341] In addition, because the reduced rotation output is connected anddisconnected in accordance with the braking of the brake B3, it ispossible to make the brake B3 compact, for example, in comparison with aclutch connecting and disconnecting the reduced rotation, and toposition the planetary gear PR and the planetary gear unit PU close toeach other. Therefore, it is possible to achieve a compact structure andweight saving in the automatic transmission 1 ₈.

[0342] Because the hydraulic servo 262 is provided on the input shaft20, it is possible to supply the oil to the oil chamber 262 a of thehydraulic servo 262 and prevent oil from leaking from the case 3 byusing the pair of sealing rings 281, and to supply the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 262. Further, the hydraulic servo 261 can supply the oilfrom the boss portions 3 c that extends from the case 3, for example,without passing it through other members, that is, the oil can besupplied by respectively arranging the pair of sealing rings 280.Accordingly, it is possible to supply the oil to the hydraulic servos262, 261 by simply providing the respective pairs of sealing rings 281,280 and it is possible to minimize the sliding resistance that resultsfrom the sealing ring, whereby it is possible to improve the efficiencyof the automatic transmission 1 ₈.

[0343] Further, because the planetary gear PR is a double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as a reduced rotation. Further, even in the case where the gear ratioof the automatic transmission 1 ₈ is set favorably, high speed rotationcan be restricted without making each of the rotation elements of theplanetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₈compact.

[0344] Additionally, because the planetary gear PR is structured so asto include the sun gear S1, that corresponds to the input rotationelement, the carrier CR1, that corresponds to the fixed element, and thering gear R1, that corresponds to the output rotation element, it ispossible to output the rotation of the input shaft 20 as the reducedrotation.

[0345] Further, as the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2, it is possible to arrange theplanetary gear PR and the planetary gear unit PU close to each otherwhile it is also possible to achieve, for example, the six forwardspeeds and the one backward speed. Accordingly, it is possible to makethe transmission member 440 that transmits the reduced rotationcomparatively short.

[0346] Further, as the one-way clutch F3 is provided in parallel to thebrake B2 and restricts the rotation of the carrier CR2 to one direction,it is possible to achieve the forward first speed, for example, at atime of normal running by engagement of the clutch C1 and the one-wayclutch F3. As a result, it is possible to smoothly achieve the forwardfirst speed, for example, at a time of changing from a non-running rangeto a running range.

[0347] Further, because the brake B2 and the one-way clutch F3 arearranged at the outer peripheral side of the planetary gear unit PU, itis possible to make the portion in which the clutches C1, C2 arearranged compact in the axial direction in comparison with the case, forexample, where the one-way clutch F3 is arranged adjacent to the clutchC2 (particularly for restricting the rotation of the hub member 223 inone direction), so that it is possible to position the counter gear 50closer to the torque converter side. Accordingly, it is possible toposition the gear 51 of the counter shaft 52 closer to the torqueconverter side, and it is possible to make the counter shaft portion 4compact in the axial direction.

[0348] Additionally, as shown in the velocity diagram, the configurationmakes it possible to realize the six forward speeds and one backwardspeed, while, at the same time, it is also possible to arrange theplanetary gear PR and the planetary gear unit PU close to each other andmake the transmission member 440, that transmits the reduced rotation,comparatively short. Accordingly, it is possible to achieve a compactstructure and weight saving in the automatic transmission 1 ₈, and it ispossible to make the inertia (the inertia force) small. Thus, it ispossible to improve the controllability of the automatic transmission 1₈ and it is possible to reduce the generation of shift shock.

[0349] Further, the configuration is able to realize the six forwardspeeds and the one backward speed, and both the clutches C1, C2 areengaged in the forward fourth speed, that is, the directly connectedstate is established in the forward fourth speed. Accordingly, it ispossible to set the gear ratio in the forward fifth speed and theforward sixth speed so that it is high. In the case, in particular, of avehicle running at a high speed for which mounting has been executed, itis possible to make the engine speed low and to contribute to quietnessof the vehicle when running at high speed.

[0350] Further, because the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4, it is possible to mount the automatictransmission 1 ₈, for example, in the FF vehicle.

[0351] Hereinafter, a description will be given, with reference to FIGS.29 to 31, of a ninth embodiment that is a partial modification of thefirst, second and fifth embodiments. It should be noted that, in theninth embodiment, with the exception of partially modified portions, thesame reference numerals denote the same elements as those of the first,second and fifth embodiments and a description thereof will be omitted.

[0352] First, a description will be given of an automatic speed changemechanism 2 ₉ of the automatic transmission 1 ₉ in accordance with theninth embodiment with reference to FIG. 29. As shown in FIG. 29, theplanetary gear unit PU and the planetary gear (the reduced rotationoutput unit, the speed reduction planetary gear) PR are provided on theinput shaft 20. The planetary gear unit PU is a so-called Ravigneauxtype planetary gear having four rotation elements, namely, a sun gear (athird rotation element, a second sun gear) S2, a carrier (a secondrotation element, a second carrier) CR2, a ring gear (a fourth rotationelement, a second ring gear) R2 and a sun gear (a first rotationelement, a third gear) S3. The carrier CR2 is provided with, in anintermeshing manner, a long pinion PL supported by side plates 542, 544and meshed with the sun gear S2 and the ring gear R2, and a short pinionPS meshed with the sun gear S3. Further, the planetary gear PR is aso-called double pinion planetary gear having a carrier (an inputrotation element, a first carrier) CR1 that is provided with, in anintermeshing manner, a pinion P2 which meshes with a ring gear (anoutput rotation element, a first ring gear) R1 and a pinion P1 whichmeshes with a sun gear (an input rotation element, a first sun gear) S1.

[0353] A multiple disc clutch (a first clutch) C3, having a hydraulicservo 565, a friction disk 572, a drum-like member 522 forming a clutchdrum (a first clutch drum), and a hub member (a member connected to thesecond rotation element) 523 connected to the carrier CR2, is arrangedon the input shaft 20 at an inner peripheral side. A multiple discclutch (a second clutch) C2, having a hydraulic servo 262, a frictiondisk 571, a drum member 524 forming a clutch drum (a second clutchdrum), and a hub member (a member connected to the third rotationmember) 525 connected to the sun gear S2 is arranged at an outerperipheral side of the clutch C3.

[0354] The hydraulic servo 565 is configured from a piston member (afirst piston) 565 b that presses the friction disk 272, a drum-likemember 522 having a cylinder portion 565 e, an oil chamber (a firsthydraulic servo oil pressure chamber) 565 a formed between the pistonmember 565 b and the cylinder portion 565 e and sealed by sealing rings565 f, 565 g, a return spring 565 c that energizes the piston member 565b in the direction of the oil chamber 565 a, and a return plate 565 dthat receives the energy of the return spring 565 c. The oil chamber 565a communicates with the oil passages 20 a, 20 b formed in the inputshaft 20. The oil passage 20 a extends to one end of the case 3, andcommunicates with an oil passage 591 of the boss portion 3 c provided onthe input shaft 20 so as to have a sleeve shape. Further, the oilpassage 591 communicates with the hydraulic control apparatus (notshown). In other words, because the hydraulic servo 565 is arranged onthe input shaft 20, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 565 a is configured by a pair of sealingrings 581 sealing a portion between the boss portion 3 c of the case 3and the input shaft 20.

[0355] Further, the hydraulic servo 562 is configured from a pistonmember (a second piston) 562 b that presses the friction disk 271, adrum-like member 524 having a cylinder member 562 e, an oil chamber (asecond hydraulic servo oil pressure chamber) 562 a formed between thepiston member 562 b and the cylinder member 562 e and sealed by sealingrings 562 f, 562 g, a return spring 562 c that energizes the pistonmember 562 b in the direction of the oil chamber 562 a, and a returnplate 562 d that receives the energy of the return spring 562 c. The oilchamber 562 a communicates with an oil passage 592 of the boss portion 3c, and the oil passage 592 communicates with the hydraulic controlapparatus (not shown). In other words, in the hydraulic servo 562, anoil passage from the hydraulic control apparatus (not shown) to the oilchamber 562 a is configured by a pair of sealing rings 580 sealing aportion between the boss portion 3 c of the case 3 and the cylindermember 562 e.

[0356] Further, a multiple disc brake (a third brake) B2 having ahydraulic servo 563 and a friction disk 574 is arranged at an outerperipheral side of the hub member 525. The hydraulic servo 563 isconfigured from a piston member 563 b that presses the friction disk574, a cylinder portion 563 e formed in a part of the case 3 b, an oilchamber 563 a formed between the piston member 563 b and the cylinderportion 563 e and sealed by sealing rings 562 f, 563 g, a return spring563 c that energizes the piston member 563 b in the direction of the oilchamber 563 a, and a return plate 563 d that receives the energy of thereturn spring 563 c.

[0357] In other words, the drum-like member 522 described above isconnected to the input shaft 20, and the clutch C3 that can beselectively engaged by the hydraulic servo 565 for the clutch C3 isarranged so as to be spline engaged at an inner peripheral side of aleading end portion of the drum-like member 522, and an inner peripheralside of the clutch C3 is connected by spline engagement to the hubmember 523. Further, the hub member 523 is connected to the sun gear S2.Additionally, the clutch C2 that can be selectively engaged by thehydraulic servo 562 for the clutch C2 is arranged so as to be splineengaged at an inner peripheral side of a leading end portion of thedrum-like member 524, and the hub member 525 is connected by splineengagement to the inner peripheral side of the clutch C2. Further, thebrake B2, that can be selectively engaged by the hydraulic servo 563 forthe brake B2, is arranged so as to be spline engaged at an outerperipheral side of the drum-like member 525. Further, the hub member 525is connected to the carrier CR2.

[0358] On the other hand, a multiple disc clutch (a third clutch) C1having a hydraulic servo 561, a friction disk 575, and a drum-likemember 531 forming a clutch drum (a third clutch drum) is arranged onthe other end (the left side in the drawing) of the input shaft 20. Thehydraulic servo 561 is configured from a piston member 561 b thatpresses the friction disk 575, a drum-like member 531 having a cylinderportion 561 e, an oil chamber 561 a formed between the piston member 561b and the cylinder portion 561 e and sealed by sealing rings 561 f, 561g, a return spring 561 c that energizes the piston member 561 b in thedirection of the oil chamber 561 a, and a return plate 561 d thatreceives the energy of the return spring 561 c. Note that, a clutch drumconfigured from the drum-like member 531 is open in the direction of theplanetary gear PR, and the planetary gear PR is arranged between thehydraulic servo 561 and the planetary gear unit PU in an axialdirection. Further, the friction disk 575 is positioned such that itoverlaps with the planetary gear PR at an outer diameter side in adiametrical direction.

[0359] The oil chamber 561 a extends to the other end of the case 3 atthe opposite side to the boss portion 3 c, and communicates with an oilpassage 593 of the boss portion 3 d provided surrounding the input shaft20 so as to have a sleeve shape, and the oil passage 593 communicateswith the hydraulic control apparatus (not shown). In other words, in thehydraulic servo 561, an oil passage from the hydraulic control apparatus(not shown) to the oil chamber 561 a is configured by a pair of sealingrings 582 sealing a portion between the boss portion 3 d of the case 3and the drum-like member 532 having the cylinder portion 561 e.

[0360] That is, the drum-like member 531 is rotatably supported by theboss portion 3 d, and the clutch C1 that can be selectively engaged bythe hydraulic servo 561 for the clutch C1 is arranged so as to be splineengaged at an inner peripheral side of a leading end portion of thedrum-like member 561. The hub member 532, in which the ring gear R1 isformed, is arranged at the inner peripheral side of the clutch C1 so asto be spline engaged, and the hub member 532 is rotatably supported bythe boss portion 3 d. Further, the carrier CR1 has the pinion P1 and thepinion P2; the pinion P2 meshes with the ring gear R1, and the pinion P1meshes with the sun gear S1 connected to the input shaft 20. The carrierCR1 is fixed to the case 3 b via the side plate 633.

[0361] Further, the drum-like member 531 with which the clutch C1 isspline engaged is rotatably supported on the boss portion 3 d, thetransmission member 540 that transmits the rotation of the ring gear R1is connected when the clutch C1 is engaged, and the sun gear S3 of theplanetary gear unit PU is connected to the other side of thetransmission member 540.

[0362] On the other hand, a multiple disc brake (a second brake) B1,having a hydraulic servo 564, a friction disk 573, and a hub member 547,and a one-way clutch (a first one-way clutch) F3 are arranged at anouter peripheral side of the planetary gear unit PU. The hydraulic servo564 is configured from a piston member 564 b that presses the frictiondisk 573, a cylinder portion 564 e formed in a part of the case 3 b, anoil chamber 564 a formed between the piston member 564 b and thecylinder portion 564 e and sealed by sealing rings 564 f, 564 g, areturn spring 564 c that energizes the piston member 564 b in thedirection of the oil chamber 564 a, and a return plate 564 d thatreceives the energy of the return spring 564 c.

[0363] In other words, the hub member 547 with which the brake B1 isspline engaged is connected to a side plate 542 of the carrier CR2 inthe planetary gear unit PU, and an inner race of the one-way clutch F3is connected to the hub member 547. Further, the ring gear R2 mesheswith the long pinion PL of the carrier CR2, the connection member 545 isconnected to one end of the ring gear R2, and the ring gear R2 isconnected to the counter gear 50 via the connection member 545.

[0364] As described above, the planetary gear PR is arranged at one sideof the planetary gear unit PU in an axial direction, the clutch C2, theclutch C3 and the brake B2 are arranged at the other side in the axialdirection, and the counter gear 50 is arranged between the clutch C2,the clutch C3, the brake B2 and the planetary gear unit PU. Further, theclutch C1 is arranged at the outer peripheral side of the planetary gearPR, and the brake B2 is arranged at the outer peripheral side of theplanetary gear unit PU, respectively. Further, the planetary gear PR,the planetary gear unit PU and the counter gear 50 are providedcoaxially with the input shaft 20.

[0365] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₉ with reference to FIGS. 29, 30 and31 on the basis of the structure described above. Note that, in thevelocity diagram shown in FIG. 31, the vertical axis indicates arotation speed of each of the rotation elements, and the horizontal axisindicates and corresponds to a gear ratio of each of the rotationelements. Further, in the portion for the planetary gear unit PU in thevelocity diagram, the vertical axis of the endmost portion in thehorizontal direction (the right side in FIG. 31) corresponds to the sungear S3, and from there toward the left side in the drawing, thevertical axes correspond to the ring gear R2, the carrier CR2 and thesun gear S2, respectively.

[0366] As shown in FIG. 29, the rotation of the input shaft 20 is inputto the sun gear S2 in accordance with the engagement of the clutch C2,and the sun gear S1 can have its rotation selectively fixed inaccordance with braking of the brake B1. The rotation of the input shaft20 is input to the carrier CR2 in accordance with the engagement of theclutch C3, and the carrier CR2 can have its rotation selectively fixedin accordance with braking of the brake B2, and has its rotationrestricted in one direction by the one-way clutch F3.

[0367] On the other hand, the sun gear S1 is connected to the inputshaft 20 and the rotation of the input shaft 20 is input to the sun gearS1. The carrier CR1 is connected to the case 3 b and has its rotationfixed. Accordingly, the ring gear R1 is rotated at a reduced speed.Further, the reduced rotation of the ring gear R1 is input to the sungear S3 in accordance with the engagement of the clutch C1.

[0368] Further, the rotation of the ring gear R2 is output to thecounter gear 50, and is output to the driven wheel (not shown) via thecounter gear 50, the counter shaft portion 4 and the differentialportion 5 (refer to FIG. 1).

[0369] In the forward first speed in the drive (D) range, as shown inFIG. 30, the clutch C1 and the one-way clutch F3 are engaged.Accordingly, as shown in FIG. 31, the reduced rotation of the ring gearR1 is input to the sun gear S3 via the transmission member 540. Further,the rotation of the carrier CR2 is restricted to one direction (aforward rotation direction), that is, the carrier CR2 is prevented fromrotating backward, and is therefore placed in a fixed state. Further,the ring gear R2 generates a forward rotation that corresponds to theforward first speed in accordance with the reduced rotation input to thesun gear S3 and the fixed carrier CR, and the rotation is output fromthe counter gear 50.

[0370] In this case, when engine brake (coasting) takes place, the stateof the forward first speed is maintained such that the brake B1 isengaged as to fix the carrier CR2, and prevent the carrier CR2 fromrotating forward. Further, in the forward first speed, the one-wayclutch F3 prevents the carrier CR2 from rotating backward and allows itto forward rotate. Accordingly, it is possible to smoothly achieve theforward first speed, for example, at a time of changing from anon-running range to a running range, in accordance with automaticengagement of the one-way clutch F3. In this case, at this time, becausethe sun gear S3 and the ring gear R1 are rotated at the reduced speed,the transmission member 540 described above transmits a comparativelylarge torque.

[0371] In the forward second speed in the drive (D) range, as shown inFIG. 30, the clutch C1 is engaged, and the brake B2 is engaged.Accordingly, as shown in FIG. 31, the reduced rotation of the ring gearR1 is input to the sun gear S3 via the clutch C1 and the transmissionmember 540, and the rotation of the sun gear S2 is fixed by the brakeB2. Accordingly, the carrier CR2 is rotated at a slightly reduced speed,the ring gear R2 generates a forward rotation that corresponds to theforward second speed in accordance with the reduced rotation input tothe sun gear S3, and the carrier CR2 with the slightly reduced rotation,and the rotation is output from the counter gear 50. In this case, atthis time, because the sun gear S3 and the ring gear R1 are rotated atthe reduced speed, the transmission member 540 transmits a comparativelylarge torque.

[0372] In the forward third speed in the drive (D) range, as shown inFIG. 30, the clutch C1 and the clutch C2 are engaged. Accordingly, asshown in FIG. 31, the reduced rotation of the ring gear R1 is input tothe sun gear S3 via the clutch C1 and the transmission member 540, andthe rotation of the input shaft 20 is input to the sun gear S2 inaccordance with the engagement of the clutch C2. Accordingly, thecarrier CR2 is rotated at a slightly larger reduced speed than thereduced rotation of the sun gear S3 in accordance with the rotation ofthe input shaft 20 input to the sun gear S2 and the reduced rotation ofthe sun gear S3. Further, the ring gear R2 generates a forward rotationthat corresponds to the forward third speed in accordance with the inputrotation of the sun gear S2, the reduced rotation of the sun gear S3,and the rotation is output from the counter gear 50. In this case, atthis time, because the sun gear S3 and the ring gear R1 are rotated atthe reduced speed, the transmission member 540 transmits a comparativelylarge torque.

[0373] In the forward fourth speed in the drive (D) range, as shown inFIG. 30, the clutch C1 and the clutch C3 are engaged. Accordingly, asshown in FIG. 31, the reduced rotation of the ring gear R1 is input tothe sun gear S3 via the clutch C1 and the transmission member 540, andthe rotation of the input shaft 20 is input to the carrier CR2 via theclutch C3. Further, the ring gear R2 generates a forward rotation thatcorresponds to the forward fourth speed in accordance with the rotationof the input shaft 20 input to the carrier CR2, and the reduced rotationof the sun gear S3, and the rotation is output from the counter gear 50.In this case, at this time, because the sun gear S3 and the ring gear R1are rotated at the reduced speed, the transmission member 540 transmitsa comparatively large torque.

[0374] In the forward fifth speed in the drive (D) range, as shown inFIG. 30, the clutch C2 and the clutch C3 are engaged. Accordingly, asshown in FIG. 31, the rotation of the input shaft 20 is input to thecarrier CR2 via the clutch C3, and the rotation of the input shaft 20 isinput to the sun gear S2 via the clutch C2. Further, the ring gear R2generates the same forward rotation as the rotation of the input shaft20 which corresponds to the forward fifth speed, as a result of therotation of the input shaft 20 input to the sun gear S2 and the rotationof the input shaft 20 input to the carrier CR2, that is, the ring gearR2 is placed in a directly connected state, and the rotation is outputfrom the counter gear 50.

[0375] In the forward sixth speed in the drive (D) range, as shown inFIG. 30, the clutch C3 is engaged, and the brake B2 is engaged.Accordingly, as shown in FIG. 31, the rotation of the input shaft 20 isinput to the carrier CR2 via the clutch C3, and the rotation of the sungear S2 is fixed in accordance with braking of the brake B2. Further,the ring gear R2 generates an increased speed rotation that correspondsto the forward sixth speed in accordance with the rotation of the inputshaft 20 input to the carrier CR2 and the fixed sun gear S2, and therotation is output from the counter gear 50.

[0376] In the backward first speed in the reverse (R) range, as shown inFIG. 30, the clutch C2 is engaged, and the brake B1 is engaged.Accordingly, as shown in FIG. 31, the rotation of the input shaft 20 isinput to the sun gear S2 in accordance with the engagement of the clutchC2, and the rotation of the carrier CR2 is fixed in accordance withbraking of the brake B1. Further, the ring gear R2 generates a reverserotation that corresponds to the backward first speed in accordance withthe rotation of the input shaft 20 input to the sun gear S2 and thefixed carrier CR2, and the rotation is output from the counter gear 50.

[0377] In the parking (P) range and the neutral (N) range, inparticular, the clutch C1, the clutch C2 and the clutch C3 aredisengaged, and power transmission between the input shaft 20 and thecounter gear 50 is in an interrupted state. Accordingly, the entireautomatic speed change mechanism 2 ₉ of automatic transmission 1 ₉ is ina slipping state (a neutral state). In this case, the brake B1 fixingthe carrier CR2 is engaged and frequent repetition of engagement anddisengagement of the brake B1 is prevented, but does not have anyparticular influence on the rotation state of the other rotationelements within the automatic speed change mechanism 2 ₉.

[0378] As described above, with the automatic transmission 1 ₉, theplanetary gear PR, the clutch C1 and the transmission member 540 whichcorrespond to the reduced rotation output unit are arranged at one side(the left side in FIG. 29) in the axial direction of the planetary gearunit PU, the clutch C2 and the clutch C3 are arranged at the other side(the right side in FIG. 29) in the axial direction of the planetary gearunit PU, and the counter gear 50 that corresponds to the output memberis arranged between the clutch C2, the clutch C3 and the planetary gearunit PU. Accordingly, it is possible to position, in particular, theplanetary gear PR and the planetary gear unit PU close to each other,and it is possible to make the length of the transmission member 540,that transmits the reduced rotation, comparatively short in the axialdirection. Thus, it is possible to achieve a compact structure andweight saving of the automatic transmission 1 ₉ and to make the inertia(the inertia force) small in accordance with the weight saving of thetransmission member 540. Therefore, it is possible to improve thecontrollability of the automatic transmission 1 ₉ and to reduce thegeneration of shift shock.

[0379] Further, because the clutch C2 is connected to the carrier CR2through the outer peripheral side of the clutch C3, it is possible toprevent the member that connects each of the rotation elements frombeing complicated and to make the automatic transmission 1 ₉ compact.

[0380] Further, the clutch C3 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, cannot have itsdiameter enlarged at the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 565, and more particularly, thepressure receiving area of the oil chamber 565 a for the hydraulic servo565, is large at the inner peripheral side by providing the hydraulicservo 565 on the input shaft 20 (in comparison with the case, forexample, of provision on the boss portion 3 c), and it is also possibleto increase the capacity of the clutch C3.

[0381] Additionally, because the planetary gear PR, the planetary gearunit PU and the counter gear 50 are provided coaxially with the inputshaft 20, it is possible to make the driven wheel transmission mechanism(for example, the counter shaft portion 4, or the like) compact, inparticular, in the case where the automatic transmission 1 ₉ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member and to improve the ease of mounting of the automatictransmission 1 ₉.

[0382] Further, the clutch C1 connects and disconnects the output of thereduced rotation. By disengaging the clutch C3, it is possible to makethe rotation of the input shaft that is input to the sun gear S1 rotateidly using the planetary gear PR and, more particularly, using the ringgear R1, while, at the same time, it is possible to selectivelyoutputable the reduced rotation to the sun gear S3. As a result, it ispossible to directly fix the carrier CR1 to the case 3, or the like,without providing a brake and to achieve a compact structure and weightsaving for the automatic transmission 1 ₉.

[0383] Further, because the hydraulic servo 565 is provided on the inputshaft 20, it is possible to supply the oil to the oil chamber 565 a ofthe hydraulic servo 565 by preventing the oil from leaking from the case3 by using the pair of sealing rings 281, and supplying the oil to theoil passages 20 a, 20 b provided within the input shaft 20, for example,without arranging a sealing ring between the input shaft 20 and thehydraulic servo 565. Also, the hydraulic servos 562, 561 can supply theoil from the boss portions 3 c, 3 d that extend from the case 3, forexample, without passing it through other members, that is, the oil canbe supplied by respectively arranging the pairs of sealing rings 580,582. Accordingly, it is possible to supply the oil to the hydraulicservos 565, 562, 561 by simply arranging the respective pairs of sealingrings 581, 580, 582 and to minimize the sliding resistance that resultsfrom the sealing ring. Thus, it is possible to improve the efficiency ofthe automatic transmission 1 ₉.

[0384] In addition, because the friction disk 575 is arranged at anouter peripheral side of the planetary gear PR in the diametricaldirection, it is possible to make the automatic transmission 1 ₉ compactin the axial direction. Further, because the planetary gear PR and theplanetary gear unit PU can be arranged adjacent to each other byarranging the planetary gear PR between the hydraulic servo 561 of theclutch C1 and the planetary gear unit PU in the axial direction (sincethe hydraulic servo 561 of the clutch C1 is not provided between theplanetary gear PR and the planetary gear unit PU), it is possible tomake the transmission member 540 comparatively short. Accordingly, it ispossible to achieve a compact structure and weight saving for theautomatic transmission 1 ₉ and to make the inertia (the inertia force)small. As a result, it is possible to improve the controllability of theautomatic transmission 1 ₉ and to reduce the generation of shift shock.

[0385] Further, because the planetary gear PR is a double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case that the gearratio of the automatic transmission 1 ₉ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₉compact.

[0386] Because the planetary gear unit PR is structured to include thesun gear S1, that corresponds to the input rotation element, the carrierCR1, that corresponds to the fixed element, and the ring gear R1, thatcorresponds to the output rotation element, it is possible to output therotation of the input shaft 20 as the reduced rotation.

[0387] Further, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2. Accordingly it is also possible torealize, for example, the six forward speeds and the one backward speed,while, at the same time, it is possible to position the planetary gearPR and the planetary gear unit PU close to each other, and make thetransmission member 540 that transmits the reduced rotationcomparatively short.

[0388] Further, the one-way clutch F3 is positioned in parallel to thebrake B1 and restricts the rotation of the carrier CR2 to one direction.Thus, it is possible to achieve, for example, the forward first speed ata time of normal running by engagement of the clutch C1 and the one-wayclutch F3 and to smoothly achieve the forward first speed, for example,at a time of changing from a non-running range to a running range.

[0389] Further, as the brake B1 and the one-way clutch F3 are arrangedat the outer peripheral side of the planetary gear unit PU, it ispossible to make the portion in which the clutches C1, C2 are arrangedcompact in the axial direction in comparison with the case, for example,where the one-way clutch F3 is arranged adjacent to the clutch C2(particularly for restricting the rotation of the hub member 523 in onedirection). As a result, it is possible to position the counter gear 50closer to the torque converter side. Therefore, it is possible toposition the gear 51 of the counter shaft 52 closer to the torqueconverter side and to make the counter shaft portion 4 compact in theaxial direction.

[0390] Further, as shown in the velocity diagram, the configurationmakes it possible to realize the six forward speeds and the one backwardspeed, while at the same time it is possible to position the planetarygear PR and the planetary gear unit PU close to each other, and make thetransmission member 540, that transmits the reduced rotation,comparatively short. Accordingly, it is possible to achieve a compactstructure and weight saving for the automatic transmission 1 ₉, and tomake the inertia (the inertia force) small. Thus, it is possible toimprove the controllability of the automatic transmission 1 ₉ and toreduce the generation of shift shock.

[0391] Further, the automatic speed change mechanism 2 ₉ is in thedirectly connected state in the forward fifth speed, that is, it canoutput reduced rotation throughout the four speeds from the forwardfirst speed to the forward fourth speed. Thus, in particular, when theautomatic speed change mechanism 2 ₉ is mounted in the vehicle, it ispossible to execute finely differentiated shifting in a low middle speedrange of the vehicle. Accordingly, in particular, in the low middlespeed range of the vehicle, it is possible to fully utilize the rotationspeed range so as to realize maximum efficiency of drive power source,for example, the engine, or the like. As a result, it is possible topromote improved fuel consumption.

[0392] In addition, because the directly connected state is achieved inthe forward fifth speed, it is possible to set only the forward sixthspeed as overdrive, and to make a final gear ratio small in comparisonwith an automatic transmission, for example, in which the directlyconnected state is achieved in the forward fourth speed, and the forwardfifth speed and the forward sixth speed constitute overdrive. Therefore,for example, it is possible to make the diameter of the differentialring gear of the differential portion 5 small and to shorten thedistance between the input shaft 20 and the shaft of the differentialportion 5. In particular, in the case that the automatic transmission 1₉ is mounted in the FF vehicle, it is possible to make the automatictransmission 1 ₉ compact.

[0393] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Accordingly, it is possible to mount theautomatic transmission 1 ₉, for example, in the FF vehicle.

[0394] Hereinafter, a description will be given, with reference to FIGS.32 to 34, of a tenth embodiment that is a partial modification of theninth embodiment. Note that, in the tenth embodiment, with the exceptionof the partially modified portions, the same reference numerals denotethe same elements as those of the ninth embodiment, and a descriptionthereof will be omitted.

[0395] As shown in FIG. 32, an automatic speed change mechanism 2 ₁₀ ofthe automatic transmission 1 ₁₀ in accordance with the tenth embodimentis structured such that the arrangement of the planetary gear (thereduced rotation output unit, the speed reduction planetary gear) PR andthe clutch (the third clutch) C1 is changed as compared to the automaticspeed change mechanism 2 ₉ in accordance with the ninth embodiment(refer to FIG. 29).

[0396] In the automatic speed change mechanism 2 ₁₀, the clutch C1 isarranged at the opposite side (the left side in the drawing) of theplanetary gear PR to the planetary gear unit PU, and an inner peripheralside of a leading end portion of a drum-like member 631 of the clutch C1is spline engaged to the friction disk 575. Further, the drum-likemember 631 of the clutch C1 is connected to the input shaft 20.

[0397] On the other hand, the sun gear (the input rotation element, thefirst sun gear) S1 is rotatably supported by the input shaft 20 and isconnected to a hub member 632. The friction disk 575 is spline engagedto an outer peripheral side of a leading end portion of the hub member632. Further, the carrier (the fixed element, the first carrier) CR1 isfixed and supported by the case 3 b such that a fixed member 633 isconnected to the side plate of the carrier CR1. Further, a transmissionmember 640 is connected to the ring gear (the output rotation element,the first ring gear) R1, and the sun gear S3 is connected via thetransmission member 640.

[0398] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₁₀ with reference to FIGS. 32, 33 and34 on the basis of the structure described above. Note that, in the samemanner as the ninth embodiment described above, in the velocity diagramshown in FIG. 34, the vertical axis indicates a rotation speed of eachof the rotation elements, and the horizontal axis indicates andcorresponds to a gear ratio of each of the rotation elements. Further,in the portion for the planetary gear unit PU in the velocity diagram,the vertical axis of the endmost portion in the horizontal direction(the right side in FIG. 34) corresponds to the sun gear S3, and fromthere toward the left side in the drawing, the vertical axes correspondto the ring gear R2, the carrier CR2, and the sun gear S2.

[0399] As shown in FIG. 32, the rotation of the input shaft 20 is inputto the sun gear S1 in accordance with the engagement of the clutch C1.Further, the carrier CR1 is fixed in rotation with respect to the case3, and the ring gear R1 described above is rotated at a reduced speed onthe basis of the rotation of the input shaft 20 input to the sun gearS1. In other words, the reduced rotation of the ring gear R1 is input tothe sun gear S3 via the transmission member 640 in accordance with theengagement of the clutch C1.

[0400] Accordingly, as shown in FIGS. 33 and 34, in the planetary gearPR, in the forward first speed, the forward second speed, the forwardthird speed and the forward fourth speed, the clutch C1 is engaged,whereby the rotation of the input shaft 20 is input to the sun gear S1,the reduced rotation is output to the ring gear R3 by the fixed carrierCR1, and the reduced rotation is input to the sun gear S3 via thetransmission member 640. At this time, because the ring gear R1 and thesun gear S3 are rotated at the reduced speed, the transmission member640 transmits a comparatively large torque. On the other hand, in theforward fifth speed, the forward sixth speed and the backward firstspeed, as the rotation of the sun gear S3 is input to the ring gear R1via the transmission member 640 and the clutch C1 is disengaged, the sungear S1 is rotated on the basis of the rotation of the ring gear R1 ineach of the respective shift speeds and the fixed carrier CR1, as shownin FIG. 34.

[0401] Note that, because the operations other than that of theplanetary gear PR are the same as the ninth embodiment described above,a description thereof will be omitted.

[0402] As described above, with the automatic speed change mechanism 2₁₀ of the automatic transmission 1 ₁₀, the planetary gear PR, the clutchC1 and the transmission member 640 which correspond to the reducedrotation output unit are arranged at one side (the left side in FIG. 32)in the axial direction of the planetary gear unit PU, the clutch C2 andthe clutch C3 are arranged at the other side (the right side in FIG. 32)in the axial direction of the planetary gear unit PU, and the countergear 50 that corresponds to the output member is arranged between theclutch C2, the clutch C3 and the planetary gear unit PU. Accordingly, itis possible to position, in particular, the planetary gear PR and theplanetary gear unit PU close to each other, and it is possible to makethe length of the transmission member 640 that transmits the reducedrotation comparatively short in the axial direction. Thus, it ispossible to achieve a compact structure and weight saving of theautomatic transmission 1 ₁₀ and to make the inertia (the inertia force)small in accordance with the weight saving of the transmission member640. As a result, it is possible to improve the controllability of theautomatic transmission 1 ₁₀ and to reduce the generation of shift shock.

[0403] Further, because the clutch C2 is connected to the carrier CR2via the outer peripheral side of the clutch C3, it is possible toprevent the member that connects each of the rotation elements frombeing complicated and to make the automatic transmission 1 ₁₀ compact.

[0404] Further, the clutch C3 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, cannot have itsdiameter enlarged at the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 565 and, more particularly, thepressure receiving area of the oil chamber 565 a for the hydraulic servo565, is large at the inner peripheral side by providing the hydraulicservo 565 on the input shaft 20 (in comparison with the case, forexample, of provision on the boss portion 3 c), and to increase thecapacity of the clutch C3.

[0405] Further, because the planetary gear PR, the planetary gear unitPU and the counter gear 50 are provided coaxially with the input shaft20, it is possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case where the automatic transmission 1 ₁₀ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member, and it is possible to improve the ease of mountingof the automatic transmission 1 ₁₀.

[0406] Further, for example, as disclosed in Japanese Patent Laid-OpenPublication No. 2001-263438, and the like, in the case where the clutchC1 is interposed between the ring gear R1 and the sun gear S3, it isnecessary to connect and disconnect the reduced rotation, so that thestructure becomes comparatively large, and a distance between theplanetary gear PR and the planetary gear unit PU is lengthened. However,as a result of interposition between the input shaft 20 and the sun gearS1, the reduced rotation output from the ring gear R1 of the planetarygear PR is connected and disconnected by connecting and disconnectingthe rotation of the input shaft 20 using the clutch C1. Accordingly, itis possible to make the clutch C1 compact, and it is possible toposition the planetary gear PR and the planetary gear unit PU atcomparatively close positions. Therefore, it is possible to make theautomatic transmission 1 ₁₀ compact.

[0407] Further, because the hydraulic servo 565 is provided on the inputshaft 20, it is possible to supply oil to the oil chamber 565 a of thehydraulic servo 565 and prevent the oil from leaking from the case 3 byusing the pair of sealing rings 281 and supplying the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 565. Further, the hydraulic servos 562, 561 can supplythe oil from the boss portions 3 c, 3 d that extend from the case 3, forexample, without passing it through other members, that is, the oil canbe supplied by respectively arranging pairs of sealing rings 580, 582.Accordingly, it is possible to supply the oil to the hydraulic servos565, 562, 561 by simply providing the respective pairs of sealing rings581, 580, 582 and it is possible to minimize the sliding resistance thatresults from the sealing ring, whereby it is possible to improve theefficiency of the automatic transmission 1 ₁₀.

[0408] Further, because the planetary gear PR is a double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case that the gearratio of the automatic transmission 1 ₁₀ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₁₀compact.

[0409] In addition, because the planetary gear PR is structured so as toinclude the sun gear S1 that corresponds to the input rotation element,the carrier CR1 that corresponds to the fixed element, and the ring gearR1 that corresponds to the output rotation element, it is possible tooutput the rotation of the input shaft 20 as the reduced rotation.

[0410] Further, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2; accordingly, it is possible toposition the planetary gear PR and the planetary gear unit PU close toeach other while at the same time it is possible to achieve, forexample, the six forward speeds and the one backward speed. Thus, it ispossible to make the transmission member 640, that transmits the reducedrotation, comparatively short.

[0411] Further, as the one-way clutch F3 is positioned in parallel tothe brake B1 and restricts the rotation of the carrier CR2 to onedirection, it is possible to achieve the forward first speed, forexample, at a time of normal running by engagement of the clutch C1 andthe one-way clutch F3. Accordingly, it is possible to smoothly achievethe forward first speed, for example, at a time of changing from anon-running range to a running range.

[0412] Further, the brake B1 and the one-way clutch F3 are arranged atthe outer peripheral side of the planetary gear unit PU. Therefore, itis possible to make the portion in which the clutches C1, C2 arearranged compact in the axial direction in comparison with the case, forexample, where the one-way clutch F3 is arranged adjacent to the clutchC2 (particularly for restricting the rotation of the hub member 523 inone direction). Therefore, it is possible to position the counter gear50 closer to the torque converter side. Accordingly, it is possible toposition the gear 51 of the counter shaft 52 closer to the torqueconverter side, and it is possible to make the counter shaft portion 4compact in the axial direction.

[0413] Further, as shown in the velocity diagram, the configurationmakes it possible to realize the six forward speeds and the one backwardspeed, while, at the same time, it is possible to position the planetarygear PR and the planetary gear unit PU close to each other and to makethe transmission member 640, that transmits the reduced rotation,comparatively short. Accordingly, it is possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₁₀, and itis possible to make the inertia (the inertia force) small. Thus, it ispossible to improve the controllability of the automatic transmission 1₁₀ and to reduce the generation of shift shock.

[0414] Further, the automatic speed change mechanism 2 ₁₀ is in thedirectly connected state in the forward fifth speed, that is, it canoutput the reduced rotation throughout the four speeds from the forwardfirst speed to the forward fourth speed. Thus, in particular, when theautomatic transmission 1 ₁₀ is mounted in the vehicle, it is possible toexecute finely differentiated shifting in the low middle speed range ofthe vehicle. Accordingly, in particular, in the low middle speed rangeof the vehicle, it is possible to fully utilize the rotation speed rangeso as to realize maximum efficiency of the drive power source, forexample, the engine. As a result, it is possible to promote improvedfuel consumption. Further, because the directly connected state isachieved in the forward fifth speed, it is possible to set only theforward sixth speed as overdrive and to make a final gear ratio small incomparison with an automatic transmission, for example, in which thedirectly connected state is achieved in the forward fourth speed, andthe forward fifth speed and the forward sixth speed constituteoverdrive. Therefore, for example, it is possible to make the diameterof the differential ring gear of the differential portion 5 small and toshorten the distance between the input shaft 20 and the shaft of thedifferential portion 5. In particular, in the case that the automatictransmission 1 ₁₀ is mounted in the FF vehicle, it is possible to makethe automatic transmission 1 ₁₀ compact.

[0415] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Accordingly, it is possible to mount theautomatic transmission 1 ₁₀, for example, in the FF vehicle.

[0416] Hereinafter, a description will be given, with reference to FIGS.35 to 37, of an eleventh embodiment that is a partial modification ofthe ninth embodiment. Note that, in the eleventh embodiment, with theexception of the partially modified portions, the same referencenumerals denote the same elements as those of the ninth embodiment and adescription thereof will be omitted.

[0417] As shown in FIG. 35, an automatic speed change mechanism 2 ₁₁ ofthe automatic transmission 1 ₁₁ in accordance with the eleventhembodiment, in comparison to the automatic speed change mechanism 2 ₉ inaccordance with the ninth embodiment (refer to FIG. 29), is structuredsuch that the brake (the third brake) B3 is provided instead of theclutch C1, and the carrier (the fixed element, the first carrier) CR1 ofthe planetary gear (the reduced rotation output unit, the speedreduction planetary gear) PR can be selectively fixed by the brake B3.

[0418] In the automatic speed change mechanism 2 ₁₁, the brake B3 isarranged at the opposite side (the left side in the drawing) of theplanetary gear PR to the planetary gear unit PU. The brake B3 has ahydraulic servo 566, a friction disk 576 and a hub member 731. Thehydraulic servo 566 is configured from a piston member 566 b, thatpresses the friction disk 576, a cylinder portion 566 e formed in a partof the case 3 b, an oil chamber 566 a formed between the piston member566 b and the cylinder portion 566 e and sealed by sealing rings 566 f,566 g, a return spring 566 c that energizes the piston member 566 b inthe direction of the oil chamber 566 a, and a return plate 566 d thatreceives the energy of the return spring 566 c.

[0419] The hub member 731 of the brake B3 is connected to a side plate732 of the carrier CR1 and the side plate 732 is rotatably supported bythe boss portion 3 d. Further, the sun gear (the input rotation element,the first sun gear) S1, that meshes with the pinion P1 of the carrierCR1, is connected to the input shaft 20. Further, a transmission member740 is connected to the ring gear (the output rotation element, thefirst ring gear) R1, that meshes with the pinion P2 of the carrier CR1,and the sun gear S3 is connected via the transmission member 740.

[0420] Next, a description will be given of an operation of theautomatic speed change mechanism 2 ₁₁ with reference to FIGS. 35, 36 and37 on the basis of the structure described above. Note that, in the samemanner as the ninth embodiment described above, in the velocity diagramshown in FIG. 37, the vertical axis indicates a rotation speed of eachof the rotation elements, and the horizontal axis indicates andcorresponds to a gear ratio of each of the rotation elements. Further,in the portion for the planetary gear unit PU in the velocity diagram,the vertical axis of the endmost portion in the horizontal direction(the right side in FIG. 37) corresponds to the sun gear S3, and fromthere toward the left side in the drawing, the vertical axes correspondto the ring gear R2, the carrier CR2 and the sun gear S2, respectively.

[0421] As shown in FIG. 35, the carrier CR1 is fixed to the case 3 b bybraking of the brake B3. Further, the rotation of the input shaft 20 isinput to the sun gear S1, and the ring gear R1 described above isrotated at a reduced speed on the basis of the rotation of the inputshaft 20 input to the sun gear S1, as a result of fixing of the carrierCR1. In other words, the reduced rotation of the ring gear R1 is inputto the sun gear S3 via the transmission member 740 as a result of thebrake B3.

[0422] Accordingly, as shown in FIGS. 36 and 37, in the planetary gearPR, in the forward first speed, the forward second speed, the forwardthird speed and the forward fourth speed, the brake B3 is engaged,whereby the carrier CR1 is fixed, and the reduced rotation is output tothe ring gear R3 in accordance with the rotation of the sun gear S1 towhich the rotation of the input shaft 20 is input. The reduced rotationis input to the sun gear S3 via the transmission member 740. At thistime, because the ring gear R1 and the sun gear S3 are rotated at thereduced speed, the transmission member 740 transmits a comparativelylarge torque. On the other hand, in the forward fifth speed, the forwardsixth speed and the backward first speed, the rotation of the sun gearS3 is input to the ring gear R1 via the transmission member 740 and thebrake B3 is disengaged. Accordingly, the carrier CR1 is rotated on thebasis of the rotation of the ring gear R1 in each of the respectiveshift speeds and the sun gear S1 with the rotation of the input shaft20, as shown in FIG. 37.

[0423] Note that, because the operations other than that of theplanetary gear PR are the same as the ninth embodiment described above,a description thereof will be omitted.

[0424] As described above, with the automatic speed change mechanism 2₁₁ of the automatic transmission 1 ₁₁, the planetary gear PR, the brakeB3 and the transmission member 740 which correspond to the reducedrotation output unit are arranged at one side (the left side in FIG. 35)in the axial direction of the planetary gear unit PU, the clutch C2 andthe clutch C3 are arranged at the other side (the right side in FIG. 35)in the axial direction of the planetary gear unit PU, and the countergear 50, that corresponds to the output member, is arranged between theclutch C2, the clutch C3 and the planetary gear unit PU. Accordingly, itis possible to position, in particular, the planetary gear PR and theplanetary gear unit PU close to each other and to make the length of thetransmission member 740, that transmits the reduced rotation,comparatively short in the axial direction. Thus, it is possible toachieve a compact structure and weight saving in the automatictransmission 1 ₁₁ and to make the inertia (the inertia force) small inaccordance with the weight saving of the transmission member 740.Therefore, it is possible to improve the controllability of theautomatic transmission 1 ₁₁ and to reduce the generation of shift shock.

[0425] Further, because the clutch C2 is connected to the carrier CR2through the outer peripheral side of the clutch C3, it is possible toprevent the member, that connects each of the rotation elements, frombeing complicated and to make the automatic transmission 1 ₁₁ compact.

[0426] Further, the clutch C3 is structured such that the clutch C2 isarranged at the outer peripheral side thereof and, thus, cannot have itsdiameter enlarged at the outer peripheral side. However, it is possibleto ensure that the hydraulic servo 565 and, more particularly, thepressure receiving area of the oil chamber 565 a for the hydraulic servo565 large at the inner peripheral side by providing the hydraulic servo565 on the input shaft 20 (in comparison with the case, for example, ofprovision on the boss portion 3 c) and to increase the capacity of theclutch C3.

[0427] Further, as the planetary gear PR, the planetary gear unit PU andthe counter gear 50 are provided coaxially with the input shaft 20, itis possible to make the driven wheel transmission mechanism (forexample, the counter shaft portion 4, or the like) compact, inparticular, in the case where the automatic transmission 1 ₁₁ is mountedin the FF vehicle (for example, in comparison with the case that thespeed reduction planetary gear, or the like, is provided on anothershaft). Thus, for example, it is possible to prevent the driven wheeltransmission mechanism from being interfered with by, for example, avehicle body member and to improve the ease of mounting of the automatictransmission 1 ₁₁.

[0428] Further, because the reduced rotation output is connected anddisconnected in accordance with the engagement of the brake B3, it ispossible to make the brake B3 compact, for example, in comparison with aclutch connecting and disconnecting the reduced rotation. It is alsopossible to position the planetary gear PR and the planetary gear unitPU close to each other. Therefore, it is possible to achieve a compactstructure and weight saving for the automatic transmission 1 ₁₁.

[0429] Further, as the hydraulic servo 565 is provided on the inputshaft 20, it is possible to supply the oil to the oil chamber 565 a ofthe hydraulic servo 565 and prevent the oil from leaking from the case 3by using the pair of sealing rings 581, and supplying the oil to the oilpassages 20 a, 20 b provided within the input shaft 20, for example,without providing a sealing ring between the input shaft 20 and thehydraulic servo 565. Further, the hydraulic servo 562 can supply the oilfrom the boss portion 3 c that extends from the case 3, for example,without passing it through other members, that is, the oil can besupplied by respectively arranging the pair of sealing rings 580.Accordingly, it is possible to supply the oil to the hydraulic servos565, 562 by simply providing the respectively pairs of sealing rings581, 580 and to minimize the sliding resistance that results from thesealing rings. As a result, it is possible to improve the efficiency ofthe automatic transmission 1 ₁₁

[0430] Further, because the planetary gear PR is a double pinionplanetary gear, it is possible to output the rotation of the input shaft20 as the reduced rotation. Further, even in the case that the gearratio of the automatic transmission 1 ₁₁ is set favorably, high speedrotation can be restricted without making each of the rotation elementsof the planetary gear unit and the speed reduction planetary gear large.Accordingly, it is possible to make the automatic transmission 1 ₁₁compact.

[0431] In addition, because the planetary gear PR is structured so as toinclude the sun gear S1, that corresponds to the input rotation element,the carrier CR1, that corresponds to the fixed element, and the ringgear R1, that corresponds to the output rotation element, it is possibleto output the rotation of the input shaft 20 as the reduced rotation.

[0432] Further, the planetary gear unit PU is a Ravigneaux typeplanetary gear configured from the sun gear S2, the sun gear S3, thecarrier CR2 and the ring gear R2. Accordingly, it is possible toposition the planetary gear PR and the planetary gear unit PU close toeach other and it is also possible to achieve, for example, the sixforward speeds and the one backward speed. Therefore, it is possible tomake the transmission member 740, that transmits the reduced rotation,comparatively short.

[0433] Further, the one-way clutch F3 is positioned in parallel to thebrake B1 and restricts the rotation of the carrier CR2 to one direction.Accordingly, it is possible to achieve the forward first speed, forexample, at a time of normal running by engagement of the clutch C1 andthe one-way clutch F3. Thus, it is possible to smoothly achieve theforward first speed, for example, at a time of changing from anon-running range to a running range.

[0434] Further, because the brake B1 and the one-way clutch F3 arearranged at the outer peripheral side of the planetary gear unit PU, itis possible to make the portion in which the clutches C1, C2 arearranged compact in the axial direction in comparison with the case, forexample, where the one-way clutch F3 is arranged adjacent to the clutchC2 (particularly for restricting the rotation of the hub member 523 inone direction). Accordingly, it is possible to position the counter gear50 closer to the torque converter side. Therefore, it is possible toposition the gear 51 of the counter shaft 52 closer to the torqueconverter to make the counter shaft portion 4 compact in the axialdirection.

[0435] Further, as shown in the velocity diagram, the configurationmakes it possible to realize the six forward speeds and the one backwardspeed, while, at the same time, it is possible to position the planetarygear PR and the planetary gear unit PU close to each other, and make thetransmission member 740, that transmits the reduced rotation,comparatively short. Accordingly, it is possible to achieve a compactstructure and weight saving of the automatic transmission 1 ₁₁ and tomake the inertia (the inertia force) small. Therefore, it is possible toimprove the controllability of the automatic transmission 1 ₁₁ and it ispossible to reduce the generation of shift shock.

[0436] Further, the automatic speed change mechanism 2 ₁₁ is in thedirectly connected state in the forward fifth speed, that is, can outputthe reduced rotation throughout the four shift speeds from the forwardfirst speed to the forward fourth speed. Thus, in particular, when theautomatic speed change mechanism 2 ₁, is mounted in the vehicle, it ispossible to execute finely differentiated shifting in a low middle speedrange of the vehicle. Accordingly, in particular, in the low middlespeed range of the vehicle, it is possible to fully utilize the rotationspeed range so as to realize maximum efficiency of drive power source,for example, the engine, or the like. Accordingly, it is possible topromote improved fuel consumption.

[0437] Further, because the directly connected state is achieved in theforward fifth speed, it is possible to set only the forward sixth speedas overdrive, and it is possible to make a final gear ratio small incomparison with an automatic transmission, for example, in which thedirectly connected state is achieved in the forward fourth speed, andthe forward fifth speed and the forward sixth speed constituteoverdrive. Therefore, for example, it is possible to make the diameterof the differential ring gear of the differential portion 5 small and,thus, it is possible to shorten the distance between the input shaft 20and the shaft of the differential portion 5. In particular, in the casethat the automatic transmission 1 ₁₁ is mounted in the FF vehicle, it ispossible to make the automatic transmission 1 ₁₁ compact.

[0438] Further, the driven wheel transmission mechanism has thedifferential portion 5 that outputs the rotation to the driven wheel,the counter shaft portion 4 that engages with the differential portion5, and the output member that is the counter gear that engages with thecounter shaft portion 4. Accordingly, it is possible to mount theautomatic transmission 1 ₁₁, for example, in the FF vehicle.

[0439] Note that, in the first to eleventh embodiments according to theinvention, are exemplified by the structure in which the torqueconverter 12 is provided in the automatic transmission. However, theinvention is not limited to this, and it is possible to employ anytake-off apparatus which transmits torque (rotation) at the time oftake-off. Further, a description has been given for a case in which theautomatic transmission is mounted in the vehicle having the engine asthe drive power source. However, the invention is not limited to this,the automatic transmission can be mounted in a hybrid vehicle, and itgoes without saying that any drive power source may be employed.Further, it is preferable that the automatic transmission is used in anFF vehicle. However, the invention is not limited to this, and can beused for vehicles with other drive types, such as an FR vehicle, afour-wheel drive vehicle, or the like.

[0440] Further, in the first to eleventh embodiments described above,one example was described for each of the respective structures of thereduced rotation output unit. However, in all the embodiments, it ispossible to employ any one of a structure in which the clutch isprovided between the input shaft and the input rotation element; astructure in which the clutch is provided between the reduced rotationelement and the first rotation element; a structure in which the fixedelement can be selectively engaged by the brake; and a structure inwhich the clutch is provided between the input shaft and the inputrotation element, and the fixed element can be selectively engaged bythe brake.

[0441] Further, for example, in the fifth embodiment and the sixthembodiment, a description is given of a structure in which the inputside and the output side of the automatic speed change mechanism areswitched. However, the invention is not limited to this, and a structurein which the input side and the output side of the automatic speedchange mechanism are switched can be employed in the automatictransmissions in accordance with the other embodiments.

1. An automatic transmission comprising: an input shaft that rotates onthe basis of an output rotation of a drive power source; a planetarygear unit having first, second, third and fourth rotation elements; areduced rotation output unit for selectively outputting a reducedrotation obtained by reducing rotation of the input shaft to the firstrotation element; a first clutch interposed between the input shaft andthe second rotation element; a second clutch interposed between theinput shaft and the third rotation element; and an output member thatoutputs rotation of the fourth rotation element to a driven wheeltransmission mechanism, wherein the reduced rotation output unit isarranged at one side of the planetary gear unit in an axial direction,the first and second clutches are arranged at the other side of theplanetary gear unit in the axial direction, and the output member isarranged between the first and second clutches and the planetary gearunit.
 2. The automatic transmission according to claim 1, wherein thefirst clutch is connected to the second rotation element via an innerperipheral side of the output member, and the second clutch is connectedto the third rotation element via an outer peripheral side of the firstclutch and an inner peripheral side of the output member.
 3. Theautomatic transmission according to claim 2, wherein the first clutchhas a friction disk that is spline engaged at an inner peripheral sideto a member that connects to the second rotation element; a first clutchdrum which internally houses a hydraulic servo, which is spline engagedto an outer peripheral side of the friction disk, and which is connectedto the input shaft; a first piston that presses the friction disk; and afirst hydraulic servo oil pressure chamber which is formed between aninner peripheral side of the first piston and the input shaft andbetween an outer peripheral side and the first clutch drum by sealing ina fluid tight manner, and the second clutch has a friction disk that isspline engaged at an inner peripheral side to the first clutch drum; asecond clutch drum which internally houses a hydraulic servo, which isspline engaged to an outer peripheral side of the friction disk, andwhich is connected to the third rotation element; a second piston thatpresses the friction disk; and a second hydraulic servo oil pressurechamber formed between an inner peripheral side and an outer peripheralside of the second piston and the second clutch drum by sealing in afluid tight manner.
 4. The automatic transmission according to claim 2,wherein the first clutch has a friction disk which is spline engaged atan inner peripheral side to a member that connects to the secondrotation element; a first clutch drum which internally houses ahydraulic servo, which is spline engaged to an outer peripheral side ofthe friction disk, and which is connected to the input shaft; a firstpiston that presses the friction disk; and a first hydraulic servo oilpressure chamber formed between an inner peripheral side of the firstpiston and the input shaft, and between an outer peripheral side and thefirst clutch drum by sealing in a fluid tight manner, and the secondclutch has a friction disk which is spline engaged at an innerperipheral side to the third rotation element; a second clutch drumwhich internally houses a hydraulic servo, which is spline engaged to anouter peripheral side of the friction disk, and which is arranged at anouter peripheral side of the first clutch drum and connected to theinput shaft; a second piston that presses the friction disk; and asecond hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the second piston andthe second clutch drum by sealing in a fluid tight manner.
 5. Theautomatic transmission according to claim 2, wherein the reducedrotation output unit has a speed reduction planetary gear, and the speedreduction planetary gear, the planetary gear unit and the output memberare provided coaxially with the input shaft.
 6. The automatictransmission according to claim 5, wherein the reduced rotation outputunit is configured from the speed reduction planetary gear which has aninput rotation element that inputs rotation of the input shaft, a fixedelement that fixes rotation, and an output rotation element that isalways connected to the first rotation element, and a first brakecapable of fixing rotation of the fixed element, and reduced rotationcan be output by engaging the first brake. 7-10. (Canceled)
 11. Theautomatic transmission according to claim 10, wherein the first clutch,the second clutch and the third clutch have respective hydraulic servos,the hydraulic servo of the second clutch being arranged on a first bossportion that extends from one end of the case and being communicatedwith an oil passage provided in the first boss portion, the hydraulicservo of the first clutch being arranged on one end of the input shaftand being communicated with an oil passage in one end of the first bossportion or the case via an oil passage provided within the input shaft,and the hydraulic servo of the third clutch being arranged on a secondboss portion that extends from the other end of the case or the otherend of the input shaft and being communicated with an oil passageprovided in the second boss portion.
 12. The automatic transmissionaccording to claim 11, wherein the third clutch has a friction disk thatis spline engaged at an inner peripheral side to a member connected tothe input rotation element or the output rotation element of theplanetary gear; a third clutch drum which internally houses a hydraulicservo and which is spline engaged to an outer peripheral side of thefriction disk; a third piston that presses the friction disk; and afirst hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the third piston and thethird clutch drum by sealing in a fluid tight manner, and wherein thefriction disk is arranged at a position where at least a part thereofoverlaps with an outer peripheral side in a diametrical direction of thespeed reduction planetary gear, the third clutch drum is arranged so asto open in the direction of the speed reduction planetary gear, and thespeed reduction planetary gear is arranged between the hydraulic servoof the third clutch and the planetary gear unit in an axial direction.13-36. (Canceled)
 37. The automatic transmission according to claim 6,wherein the speed reduction planetary gear is configured from a doublepinion planetary gear.
 38. The automatic transmission according to claim37, wherein the speed reduction planetary gear has a first carrier thatcorresponds to the input rotation element, a first sun gear thatcorresponds to the fixed element, and a first ring gear correspondingthe output rotation element.
 39. The automatic transmission according toclaim 37, wherein the speed reduction planetary gear has a first sungear that corresponds to the input rotation element, a first carrierthat corresponds to the fixed element, and a first ring gear thatcorresponds to the output rotation element.
 40. The automatictransmission according to claim 5, wherein the reduced rotation outputunit is configured from the speed reduction planetary gear which has aninput rotation element that inputs rotation of the input shaft, a fixedelement that fixes rotation, and an output rotation element that isalways connected to the first rotation element, a third clutchinterposed between the input shaft and the input rotation element, and afirst brake capable of fixing rotation of the fixed element, and whereinreduced rotation can be output by engaging the third clutch and thefirst brake.
 41. The automatic transmission according to claim 40,wherein the first clutch, the second clutch and the third clutch haverespective hydraulic servos, the hydraulic servo of the second clutchbeing arranged on a first boss portion that extends from one end of thecase and being communicated with an oil passage provided in the firstboss portion, the hydraulic servo of the first clutch being arranged onone end of the input shaft and being communicated with an oil passage inone end of the first boss portion or the case via an oil passageprovided within the input shaft, and the hydraulic servo of the thirdclutch being arranged on the other end of the input shaft and beingcommunicated with an oil passage.
 42. The automatic transmissionaccording to claim 41, wherein the third clutch has a friction disk thatis spline engaged at an inner peripheral side to a member connected tothe input rotation element or the output rotation element of theplanetary gear; a third clutch drum which internally houses a hydraulicservo and which is spline engaged to an outer peripheral side of thefriction disk; a third piston that presses the friction disk; and afirst hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the third piston and thethird clutch drum by sealing in a fluid tight manner, and wherein thefriction disk is arranged at a position where at least a part thereofoverlaps with an outer peripheral side in a diametrical direction of thespeed reduction planetary gear, the third clutch drum is arranged so asto open in the direction of the speed reduction planetary gear, and thespeed reduction planetary gear is arranged between the hydraulic servoof the third clutch and the planetary gear unit in an axial direction.43. The automatic transmission according to claim 40, wherein the speedreduction planetary gear is configured from a double pinion planetarygear.
 44. The automatic transmission according to claim 43, wherein thespeed reduction planetary gear has a first carrier that corresponds tothe input rotation element, a first sun gear that corresponds to thefixed element, and a first ring gear corresponding the output rotationelement.
 45. The automatic transmission according to claim 43, whereinthe speed reduction planetary gear has a first sun gear that correspondsto the input rotation element, a first carrier that corresponds to thefixed element, and a first ring gear that corresponds to the outputrotation element.
 46. The automatic transmission according to claim 5,wherein the reduced rotation output unit is configured from the speedreduction planetary gear which has an input rotation element that alwaysinputs rotation of the input shaft, a fixed element that always fixesrotation, an output rotation element that always connects to the firstrotation element, and a third clutch interposed between the input shaftand the input rotation element, wherein reduced rotation can be outputby engaging the third clutch.
 47. The automatic transmission accordingto claim 46, wherein the first clutch, the second clutch and the thirdclutch have respective hydraulic servos, the hydraulic servo of thesecond clutch being arranged on a first boss portion that extends fromone end of the case and being communicated with an oil passage providedin the first boss portion, the hydraulic servo of the first clutch beingarranged on one end of the input shaft and being communicated with anoil passage in one end of the first boss portion or the case via an oilpassage provided within the input shaft, and the hydraulic servo of thethird clutch being arranged on a second boss portion that extends fromthe other end of the case or the other end of the input shaft and beingcommunicated with an oil passage provided in the second boss portion.48. The automatic transmission according to claim 47, wherein the thirdclutch has a friction disk that is spline engaged at an inner peripheralside to a member connected to the input rotation element or the outputrotation element of the planetary gear; a third clutch drum whichinternally houses a hydraulic servo and which is spline engaged to anouter peripheral side of the friction disk; a third piston that pressesthe friction disk; and a first hydraulic servo oil pressure chamberformed between an inner peripheral side and an outer peripheral side ofthe third piston and the third clutch drum by sealing in a fluid tightmanner, and the friction disk is arranged at a position where at least apart thereof overlaps with an outer peripheral side in a diametricaldirection of the speed reduction planetary gear, the third clutch drumis arranged so as to open in the direction of the speed reductionplanetary gear, and the speed reduction planetary gear is arrangedbetween the hydraulic servo of the third clutch and the planetary gearunit in an axial direction.
 49. The automatic transmission according toclaim 46, wherein the first clutch, the second clutch and the thirdclutch have respective hydraulic servos, the hydraulic servo of thesecond clutch being arranged on a first boss portion that extends fromone end of the case and being communicated with an oil passage providedin the first boss portion, the hydraulic servo of the first clutch beingarranged on one end of the input shaft and being communicated with anoil passage in one end of the first boss portion or the case via an oilpassage provided within the input shaft, and the hydraulic servo of thethird clutch being arranged on the other end of the input shaft andbeing communicated with an oil passage.
 50. The automatic transmissionaccording to claim 49, wherein the third clutch has a friction disk thatis spline engaged at an inner peripheral side to a member connected tothe input rotation element or the output rotation element of theplanetary gear; a third clutch drum which internally houses a hydraulicservo and which is spline engaged to an outer peripheral side of thefriction disk; a third piston that presses the friction disk; and afirst hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the third piston and thethird clutch drum by sealing in a fluid tight manner, and the frictiondisk is arranged at a position where at least a part thereof overlapswith an outer peripheral side in a diametrical direction of the speedreduction planetary gear, the third clutch drum is arranged so as toopen in the direction of the speed reduction planetary gear, and thespeed reduction planetary gear is arranged between the hydraulic servoof the third clutch and the planetary gear unit in an axial direction.51. The automatic transmission according to claim 46, wherein the speedreduction planetary gear is configured from a double pinion planetarygear.
 52. The automatic transmission according to claim 51, wherein thespeed reduction planetary gear has a first carrier that corresponds tothe input rotation element, a first sun gear that corresponds to thefixed element, and a first ring gear corresponding the output rotationelement.
 53. The automatic transmission according to claim 51, whereinthe speed reduction planetary gear has a first sun gear that correspondsto the input rotation element, a first carrier that corresponds to thefixed element, and a first ring gear that corresponds to the outputrotation element.
 54. The automatic transmission according to claim 5,wherein the reduced rotation output unit is configured from the speedreduction planetary gear which has an input rotation element that alwaysinputs rotation of the input shaft, a fixed element that always fixesrotation, and an output rotation element that connects to the firstrotation element, and a third clutch interposed between the firstrotation element and the output rotation element, wherein reducedrotation can be output by engaging the third clutch.
 55. The automatictransmission according to claim 54, wherein the first clutch, the secondclutch and the third clutch have respective hydraulic servos, thehydraulic servo of the second clutch being arranged on a first bossportion that extends from one end of the case and being communicatedwith an oil passage provided in the first boss portion, the hydraulicservo of the first clutch being arranged on one end of the input shaftand being communicated with an oil passage in one end of the first bossportion or the case via an oil passage provided within the input shaft,and the hydraulic servo of the third clutch being arranged on a secondboss portion that extends from the other end of the case or the otherend of the input shaft and being communicated with an oil passageprovided in the second boss portion.
 56. The automatic transmissionaccording to claim 55, wherein the third clutch has a friction disk thatis spline engaged at an inner peripheral side to a member connected tothe input rotation element or the output rotation element of theplanetary gear; a third clutch drum which internally houses a hydraulicservo and which is spline engaged to an outer peripheral side of thefriction disk; a third piston that presses the friction disk; and afirst hydraulic servo oil pressure chamber formed between an innerperipheral side and an outer peripheral side of the third piston and thethird clutch drum by sealing in a fluid tight manner, and the frictiondisk is arranged at a position where at least a part thereof overlapswith an outer peripheral side in a diametrical direction of the speedreduction planetary gear, the third clutch drum is arranged so as toopen in the direction of the speed reduction planetary gear, and thespeed reduction planetary gear is arranged between the hydraulic servoof the third clutch and the planetary gear unit in an axial direction.57. The automatic transmission according to claim 54, wherein the speedreduction planetary gear is configured from a double pinion planetarygear.
 58. The automatic transmission according to claim 57, wherein thespeed reduction planetary gear has a first carrier that corresponds tothe input rotation element, a first sun gear that corresponds to thefixed element, and a first ring gear corresponding the output rotationelement.
 59. The automatic transmission according to claim 57, whereinthe speed reduction planetary gear has a first sun gear that correspondsto the input rotation element, a first carrier that corresponds to thefixed element, and a first ring gear that corresponds to the outputrotation element.
 60. The automatic transmission according to claim 2,wherein the planetary gear unit is a Ravigneaux type planetary gear thatis configured from a second sun gear, a third sun gear, a second carrierand a second ring gear, the first rotation element is configured fromthe second sun gear which inputs the output rotation of the reducedrotation output unit, and which is selectively fixable on the basis ofengagement of the second brake, the second rotation element isconfigured from the third sun gear that inputs rotation of the inputshaft on the basis of engagement of the first clutch, the third rotationelement is configured from the second carrier which has a long pinionmeshed with the second sun gear and a short pinion meshed with the thirdsun gear, which is selectively fixable on the basis of engagement of thethird brake, and which inputs rotation of the input shaft on the basisof engagement of the second clutch, and the fourth rotation element isconfigured from the second ring gear that meshes with the long pinion.61. The automatic transmission according to claim 60, wherein a firstone-way clutch for restricting rotation of the carrier to one directionis provided in parallel to the third brake.
 62. The automatictransmission according to claim 61, wherein the third brake is arrangedat an outer peripheral side of the planetary gear unit, and the firstone-way clutch is arranged adjacent to the second clutch.
 63. Theautomatic transmission according to claim 61, wherein the third brakeand the first one-way clutch are arranged at an outer peripheral side ofthe planetary gear unit.
 64. The automatic transmission according toclaim 60, wherein the automatic transmission is provided with a secondone-way clutch which is arranged in parallel to the second brake andwhich restricts rotation of the second sun gear to one direction on thebasis of the engagement of a fourth brake.
 65. The automatictransmission according to claim 64, wherein the automatic transmissionis provided with a sleeve member which is interposed between the reducedrotation output unit and the second sun gear and which connects theoutput rotation of the reduced rotation output unit to rotation of thesecond sun gear, and an inner race of the second one-way clutch and thesleeve member are integrally formed.
 66. The automatic transmissionaccording to claim 60, wherein in a velocity diagram in which verticalaxes show respective rotation speeds of the first, second, third andfourth rotation elements and a horizontal axis indicates and correspondsto gear ratios of the first, second, third and fourth rotation elements,the first rotation element to which the reduced rotation is inputcorresponds to the vertical axis at an endmost portion in a horizontaldirection, and the third rotation element, the fourth rotation elementconnected to the output member, and the second rotation elementcorrespond in order therefrom.
 67. The automatic transmission accordingto claim 60, wherein a forward first speed is achieved on the basis ofengagement of the first clutch and the third brake, a forward secondspeed is achieved on the basis of engagement of the first clutch and thesecond brake, a forward third speed results from engagement the firstclutch and setting of a state in which reduced rotation is output fromthe reduced rotation output unit, a forward fourth speed is achieved onthe basis of engagement of the first clutch and the second clutch, aforward fifth speed results from engagement of the second clutch andsetting of a state in which reduced rotation is output from the reducedrotation output unit, a forward sixth speed is achieved on the basis ofengagement of the second clutch and the second brake, and a backwardfirst speed results from engaging the third brake and setting a state inwhich reduced rotation is output from the reduced rotation output unit,respectively.
 68. The automatic transmission according to claim 2,wherein the planetary gear unit is configured from a first simpleplanetary gear having a second sun gear, a second carrier and a secondring gear, and a second simple planetary gear having a third sun gear, athird carrier and a third ring gear, the first rotation element isconfigured from the third ring gear which inputs the output rotation ofthe double pinion planetary gear and which is selectively fixable on thebasis of engagement of the second brake, the second rotation element isconfigured from the second ring gear and the third carrier which isselectively fixable on the basis of engagement of the third brake andwhich inputs rotation of the input shaft on the basis of engagement ofthe first clutch, the third rotation element is configured from thethird sun gear and the second sun gear which inputs rotation of theinput shaft on the basis of engagement of the second clutch, and thefourth rotation element is configured from the second carrier whichmeshes with the second sun gear and the second ring gear.
 69. Theautomatic transmission according to claim 68, wherein the automatictransmission is provided with a first one-way clutch which is arrangedin parallel to the third brake and which restricts rotation of the thirdcarrier and the second ring gear to one direction.
 70. The automatictransmission according to claim 69, wherein the third brake and thefirst one-way clutch are arranged at an outer peripheral side of theplanetary gear unit.
 71. The automatic transmission according to claim70, wherein an inner race of the first one-way clutch and the secondring gear are integrally formed.
 72. The automatic transmissionaccording to claim 68, wherein the automatic transmission is providedwith a second one-way clutch which is arranged in parallel to the secondbrake and which restricts rotation of the third ring gear to onedirection on the basis of engagement of the fourth brake.
 73. Theautomatic transmission according to claim 68, wherein in a velocitydiagram in which vertical axes show respective rotation speeds of thefirst, second, third and fourth rotation elements and a horizontal axisindicates and corresponds to gear ratios of the first, second, third andfourth rotation elements, the first rotation element to which thereduced rotation is input corresponds to the vertical axis at an endmostportion in a horizontal direction, and the third rotation element, thefourth rotation element connected to the output member, and the secondrotation element correspond in order therefrom.
 74. The automatictransmission according to claim 68, wherein a forward first speed isachieved on the basis of engagement of the second clutch and the thirdbrake, a forward second speed is achieved on the basis of engagement ofthe second clutch and the second brake, a forward third speed resultsfrom engagement of the second clutch and setting a state in whichreduced rotation is output from the reduced rotation output unit, aforward fourth speed is achieved on the basis of engagement of the firstclutch and the second clutch, a forward fifth speed results fromengagement of the first clutch and setting a state in which reducedrotation is output from the reduced rotation output unit, a forwardsixth speed is achieved on the basis of engagement of the first clutchand the second brake, and a backward first speed results from engagementof the third brake and setting a state in which reduced rotation isoutput from the reduced rotation output unit, respectively.
 75. Theautomatic transmission according to claim 2, wherein the planetary gearunit is a Ravigneaux type planetary gear configured from a second sungear, a third sun gear, a second carrier and a second ring gear, thefirst rotation element is configured from the third sun gear which iscapable of inputting the output rotation of the reduced rotation outputunit, the second rotation element is configured from the second carrierwhich has a long pinion meshed with the second sun gear and a shortpinion meshed with the third sun gear, which is selectively fixable onthe basis of engagement of the second brake, and which inputs rotationof the input shaft on the basis of engagement of the first clutch, thethird rotation element is configured from the second sun gear whichinputs rotation of the input shaft on the basis of engagement of thesecond clutch and which is selectively fixable on the basis ofengagement of the third brake, and the fourth rotation element isconfigured from the second ring gear which meshes with the long pinion.76. The automatic transmission according to claim 75, wherein a firstone-way clutch for restricting rotation of the second carrier to onedirection is provided in parallel to the second brake.
 77. The automatictransmission according to claim 76, wherein the second brake and thefirst one-way clutch are arranged at an outer peripheral side of theplanetary gear unit.
 78. The automatic transmission according to claim75, wherein in a velocity diagram in which vertical axis showsrespective rotation speeds of the first, second, third and fourthrotation elements and a horizontal axis indicates and corresponds togear ratios of the first, second, third and fourth rotation elements,the first rotation element to which reduced rotation is inputcorresponds to the vertical axis at an endmost portion in a horizontaldirection, and the fourth rotation element connected to the outputmember, the second rotation element, and the third rotation elementcorrespond in order therefrom.
 79. The automatic transmission accordingto claim 1, wherein a forward first speed results from engaging thesecond brake and setting a state in which reduced rotation is outputfrom the reduced rotation output unit, a forward second speed resultsfrom engaging the third brake and setting a state in which reducedrotation is output from the reduced rotation output unit, a forwardthird speed results from engaging the second clutch and setting a statein which the reduced rotation is output from the reduced rotation outputunit, a forward fourth speed results from engaging the first clutch andsetting a state in which the reduced rotation is output from the reducedrotation output unit, a forward fifth speed is achieved on the basis ofengagement of the first clutch and the second clutch, a forward sixthspeed is achieved on the basis of engagement of the first clutch and thethird brake, and a backward first speed is achieved on the basis ofengagement of the second clutch and the second brake, respectively. 80.The automatic transmission according to claim 1, wherein the drivenwheel transmission mechanism has a differential portion that outputsrotation to the driven wheel, and a counter shaft portion that engageswith the differential portion, and the output member is configured froma counter gear that engages with the counter shaft portion.